ICS Part 1 Physics English Medium Chapter 3 Online Short Questions Test with Answers

• Ans 1:

Motion with constant velocity is a special case of motion with constant acceleration.Is this statement true?

• Ans 1: Yes, this statement is true. When a body moves with constant velocity in the straight line, its acceleration is zero.Hence,The acceleration of the body will always remain constant during such motion.As the zero is a constant quantity, therefore this is a special case of motion.

Name the quantities which can be calculated from velocity-time graph and these can be calculated ?

• Ans 1: Distance moved by the body and its acceleration can be calculated by the velocity-time graph.
  Area under the velocity time graph line is equal to the distance covered by the body. Slope of the tangent at any point gives the instantaneous acceleration at that point.

Find a relation for magnitude of velocity of projectile and direction of projectile?

• Ans 1:

Differentiate between distance and displacement.

• Ans 1:
  

An object is thrown vertically upward.Discuss the sign of acceleration due to gravity, relative to velocity, while the object is in air.

• Ans 1: When the object is thrown vertically upward, it will move against the direction of gravity. The sign of acceleration due to gravity relative to velocity will be taken as negative. When the object is moving downward, the sign of acceleration due to gravity will be positive.

Define elastic and inelastic collisions.

• Ans 1: Elastic collisions: A collision in which the K.E. Of the system is conserved is called elastic collision.
  Inelastic collisions: A collision in which the K.E.of the system is not conserved is called inelastic collision.

Define maximum height of projectile? Derive a mathematical expression for maximum height of projectile ?

• Ans 1:

Behaviour of bouncing ball?

• Ans 1: When a hard ball is dropped onto a marble floor, it rebounds to very nearly the initial height. It loses negligible amount of energy in the collision with the floor.Then such collision is approximately an elastic collision. But if the ball is not able to reach the initial height such as collision with the sand then there is a loss of kinetic energy and such collision is called inelastic collision.

Why Newton's first law of motion is known as law of inertia?

• Ans 1: Newton's first law of motion is:
  A body at rest will remain at rest and a body moving with uniform velocity will continue to do so unless acted upon by some unbalanced external force.
  It is based on mass and inertia is the quantitative measure of an object's mass. So Newton's first law of motion is also Known as law of inertia.

Discuss the velocity-Time Graph ?

• Ans 1:

Differentiate between distance and displacement.

• Ans 1:
  

Define Impulse ? Show that impulse is equal to change in momentum show that J= P

• Ans 1: Impulse: The product of forces and duration of time in which the force acts is known as impulse.

What is the effect on the speed of a fighter plane chasing another when it opens the fire? What happens to the speed of purdued plane when it returns the fire?

• Ans 1: When the fighter plane opens fire, its momentum will be in back direction due to reaction force in backwards direction and therefore its speed will decrease.
  When the pursued plane opens fire in the backward direction, the momentum will act on the plane in forward direction due to reaction and therefore its speed will increase.

Behaviour of bouncing ball?

• Ans 1: When a hard ball is dropped onto a marble floor, it rebounds to very nearly the initial height. It loses negligible amount of energy in the collision with the floor.Then such collision is approximately an elastic collision. But if the ball is not able to reach the initial height such as collision with the sand then there is a loss of kinetic energy and such collision is called inelastic collision.

What is the change in total energy during elastic or inelastic collisions?

• Ans 1: The total energy of the system remains conserved during both type of collisions. But in an inelastic collision, some of the kinetic energy is lost .

Discuss the displacement-time Graph?

• Ans 1:

Write any two properties of inertial frame of reference.

• Ans 1:
  1. A non-accelerated frame of reference is an inertial frame of reference.
  2. Newton's 1st law of motion holds good in an inertial frame of reference.

What is the difference between uniform and variable velocity?

• Ans 1: Uniform Velocity: A body is said to have a uniform velocity if it covers equal displacement in equal intervals of time.
  
  
  Variable Velocity: A body is said to have a variable velocity if it covers unequal displacements in equal intervals of time.

Why a safety helmet of a motor cycle's is padded?

• Ans 1: A motor cycle's safety helmet is padded so as to extend the time of collision to prevent serious injury.

At what point or points in its path does a projectile have its minimum speed,its maximum speed?

• Ans 1: The speed of the projectile is minimum at the maximum height of projectile. It is because of the reason that; at maximum height the vertical component of velocity becomes zero.
  The speed of the projectile is maximum at the point of projection and also just before it strikes the ground because the vertical component of velocity is maximum at these points.

What is Ballistic Flight and Ballistic Missile?

• Ans 1: The flight in which projects is given an initial and is then allowed to move freely due to inertia and under the action of gravity is called ballistic flight.
  Ballistic missile is an unpowered and unguided missile.The flight of Ballistic missile is Ballistic flight.

Behaviour of bouncing ball?

• Ans 1: When a hard ball is dropped onto a marble floor, it rebounds to very nearly the initial height. It loses negligible amount of energy in the collision with the floor.Then such collision is approximately an elastic collision. But if the ball is not able to reach the initial height such as collision with the sand then there is a loss of kinetic energy and such collision is called inelastic collision.

Under what condition, the instantaneous and average velocities of a moving object become equal?

• Ans 1: For a body moving with uniform velocity, its average and instantaneous velocities are equal.

Discuss the momentum changes produced by explosive forces ?

• Ans 1: There are many cases where momentum changes are produced by explosive forces within an isolated system. It can be explain with the help of following Example:
  When a sheel explodes in mind-air its fragment fly apart in different direction. the various forces which occur in the explosion have zero resultant, because they cancel the effect of each other. so the total moments of the fragments is equal to the initial momentum of the sheel.

Find a relation for magnitude of velocity of projectile and direction of projectile?

• Ans 1:

Define Impulse ? Show that impulse is equal to change in momentum show that J= P

• Ans 1: Impulse: The product of forces and duration of time in which the force acts is known as impulse.

Define linear momentum ? Express Newton,s 2nd Law in terms of momentum?

• Ans 1:

State and explain Newton's second law of motion.

• Ans 1:

What is the effect on the speed of a fighter plane chasing another when it opens the fire? What happens to the speed of purdued plane when it returns the fire?

• Ans 1: When the fighter plane opens fire, its momentum will be in back direction due to reaction force in backwards direction and therefore its speed will decrease.
  When the pursued plane opens fire in the backward direction, the momentum will act on the plane in forward direction due to reaction and therefore its speed will increase.

What is projectile motion? In what direction acceleration is zero in this motion?

• Ans 1: It is the two dimensional motion in which the object moves under constant acceleration due to gravity.
  The acceleration in horizontal direction is zero in projectile motion.

Define ballistics flight and ballistic trajectory.

• Ans 1: The flight in which projectile is given an initial push and is then allowed to move freely due to inertia and under the action of gravity is called ballistic flight and the path followed by it is called ballistic trajectory.

Discuss the condition of equilibrium ?

• Ans 1:
  Newtons 1st Law of motion: This Law states that "A body at rest will remain at rest and a body in motion will continue its motion with uniform velocity unless it is acted upon by some unbalanced external force
  If F = 0 Then a = 0
  Explanation: The Ist law of motion is also known as law of inertia. The inertia is the property of a body which opposes any change in its state of motion or rest. Actually, when some force is applied on a body for changing its state of rest or uniform motion, then the body will affer resistance against this change. In the word, We can say that all the bodies try to maintain its state of rest or continue its uniform motion due to inertia. That is the why the newtons Ist law is also known as law of inertia.
  Examples:When we give a jerk to the branch of a tree, then the fruit falls down. It is because, when we give a jerk, the branch of the tree comes into motion suddenly.
  When a bus starts motion suddenly, the passengers experience a push in the back ward direction It is because, when the bus starts motion suddenly, the lower parts of the passenger in contact with the seats also come into motion. while the upper parts of the passengers are at remain at the rest In this attempt, they falls in the back words directions
  Newton's 2nd Law of motion:
  Statements: This law states that, "when a force is applied on a body, then acceleration is produced in the body in the direction of applied force and inversely proportional to the mass of the body.
  Explanation: The Ist Law of motion gives us the quantitative measurements of force, While the 2nd law of motion gives us the quantitative measurements of forces. now if the direction of motion of the body and direction of motion of the body and direction of forces are the same, then its velocity and acceleration increases. If the direction of motion of the body and direction of force are opposite in direction of force are opposite in direction, then the velocity and acceleration of the body will decreases gradually and finally become zero and the body will come to rest
  Example of newtons 2nd law of motion:
  
  When a body falls on a solid floor from the top of a building, the body experience or feel great pain. It is because, when the body falls on the floor, its acceleration become zero suddenly and the body faces huge force for very short period of time
  Newton,s 3rd Law of motion:
  This Law states that for every action, there is always a reaction. These forces are equal in magnitude but opposite in direction.
  Explanation: This law tells us that no body can experience a force from its surrounding, until this body exerts any force on its surrounding It means That forces are exerted in pairs.

Why a safety helmet of a motor cycle's is padded?

• Ans 1: A motor cycle's safety helmet is padded so as to extend the time of collision to prevent serious injury.

Differentiate between distance and displacement.

• Ans 1:
  

How is the distance calculated from velocity time graph?

• Ans 1: Area under the velocity time graph line is equal to the distance covered by the body.

What is a Ballistic Flight?

• Ans 1: The flight in which projectile is given an initial push and is then allowed to move freely due to inertia and under the action of gravity is called ballistic flight and the path followed by it is called ballistic trajectory

What is ballistic missile? Define ballistic trajectory.

• Ans 1: The missile in which it is given an initial push and is then allowed to move freely due to inertia and under the action of gravity is called ballistic and the path followed by such a projectile is called ballistic trajectory.

Write solid reasons for the loss of kinetic energy in an inelastic collision.

• Ans 1: In case of inelastic collision, the loss of kinetic energy is due to
  1. Friction of ball with floor
  2. Friction of ball with air
  3. sound

Define inertial and non-inertial frame of references.

• Ans 1: Inertial Frame of References: The frame of reference in which Newton's first law holds is called inertial frame of reference. It is not an accelerated frame of reference.e.g,, Earth is approximately an inertial frame of reference.
  Non-Inertial Frame of Reference: The frame of reference in which Newton's first law does not hold true is called non-inertial frame of reference.It is an accelerated frame of reference e.g., Space ship etc.

Define Distance and displacement ?

• Ans 1: Distance:The length of actual path traversed by a body in motion is known as distance. The actual path may be straight or cured. The distance is a scalar quantity. Its S.I units is meter.
  Displacement:The shortest distance between is know as displacement.
  A body reaches from point 'O' to 'C' through 'A" and 'B'. Thus the path 'OABC' represents the actual path traversed by the body during its motion. So it is called distance. While 'oc' represents the shortest distance between the initial point 'o' and final point 'c' It S.I unit is meter

Define ballistics flight and ballistic trajectory.

• Ans 1: The flight in which projectile is given an initial push and is then allowed to move freely due to inertia and under the action of gravity is called ballistic flight and the path followed by it is called ballistic trajectory.

What is projectile motion? In what direction acceleration is zero in this motion?

• Ans 1: It is the two dimensional motion in which the object moves under constant acceleration due to gravity.
  The acceleration in horizontal direction is zero in projectile motion.

What is the difference between uniform and variable velocity?

• Ans 1: Uniform Velocity: A body is said to have a uniform velocity if it covers equal displacement in equal intervals of time.
  
  
  Variable Velocity: A body is said to have a variable velocity if it covers unequal displacements in equal intervals of time.

Define the following terms?

Acceleration

Uniform Acceleration

Variable Acceleration

Radical Acceleration

Linear Acceleration

Positive Acceleration

Negative Acceleration

Instantaneous Acceleration

• Ans 1: Acceleration:The rate of change of velocity is known as acceleration.
  Mathematically, we have
  Acceleration = v/t It is a vector quantity. It SI unit m/sec²
  Dimensions of acceleration:We know that
  V= Displacement / time = m/sec= Length / Time
  V=[L T^-1]
  Dimensions of acceleration:We Known that
  a = Velocity/time = m/sec . sec = m/sec^-2
  a = Length/time² a = [L T^-2]
  Uniform Acceleration:A body is said to be moving with the uniform acceleration if equal change occurs in velocity in equal intervals of time.
  Variable Acceleration:A body is said to be moving with variable Acceleration if unequal change occurs in velocity in equal intervals intervals of time.
  Linear Acceleration:The acceleration which is produced due to change in magnitude of velocity is known as linear acceleration.
  Radical Acceleration:The acceleration which is produced due to change indirection of velocity is known as radical acceleration.
  Positive Acceleration:The acceleration is said to be positive if the magnitude of velocity increases with respect to time.
  Negative Acceleration:The acceleration will be magnitude of velocity decreases with respect to time.
  InstantaneousAcceleration:The acceleration of a body at any particular instant of time is known as instantaneous acceleration.

Behaviour of bouncing ball?

• Ans 1: When a hard ball is dropped onto a marble floor, it rebounds to very nearly the initial height. It loses negligible amount of energy in the collision with the floor.Then such collision is approximately an elastic collision. But if the ball is not able to reach the initial height such as collision with the sand then there is a loss of kinetic energy and such collision is called inelastic collision.

What are the factors upon which force due to water depend?

• Ans 1: Force due to water flow depends upon viscosity of the media and velocity of the fluid.

Discuss the displacement-time Graph?

• Ans 1:

Define rest and motion ?

• Ans 1: Rest:A body is said to be at rest if it do not change its position with respect to the surrounding.
  Motion:A body is said to be in motion if it change its position with respect to the surrounding.

Write two object?

• Ans 1: Velocity time graph can be used to
  
  1. Calculate the distance covered by the body .
  2. Find the instantaneous acceleration of the body.

Name the quantities which can be calculated from velocity-time graph and these can be calculated ?

• Ans 1: Distance moved by the body and its acceleration can be calculated by the velocity-time graph.
  Area under the velocity time graph line is equal to the distance covered by the body. Slope of the tangent at any point gives the instantaneous acceleration at that point.

Define the following terms?

Position,

Uniforms

speed,

variable speed

average speed,

Instantaneous speed,

• Ans 1: Position:The location of an object relative to some reference point origin is known as position.
  Speed:The distance between covered by a moving body in one second is known as speed
  Speed = Distance covered /Time
  The speed is a scalar quantity. Its S.I unit is " m/sec" .
  Uniform Speed:A body is said to be moving with uniform speed, if it equal distance in equal intervals of time.
  Variable Speed:A body is said to be moving with variable speed if it covers unequal distance in equal intervals of time.
  Average Speed:The average speed of a moving body can be atained by dividing total distance covered by total time taken
  Instantaneous Speed:The speed of a body at any particular instant of time is known as instantaneous speed.

Write two object?

• Ans 1: Velocity time graph can be used to
  
  1. Calculate the distance covered by the body .
  2. Find the instantaneous acceleration of the body.

Derive the 3rd equation of motion?

• Ans 1:

What are the factors upon which force due to water depend?

• Ans 1: Force due to water flow depends upon viscosity of the media and velocity of the fluid.

Define Collision ? Discuss the type of collision?Give example in each case?

• Ans 1: Collision:When two or more than two bodies come so closer to each other that there exists some type of interaction between them in the presence or absence of external forces then such type of interaction is known as collision.
  Type of Collision:There are two type of collision, which are given below.
  Elastic Collision:The Collision in which the momentum and kinetic energy both are conserved is known as elastic collision.
  Examples:
  1. collision of steel balls,
  2. Collision of atoms,
  3. Collision of molecules.

  Inelastic Collision:The Collision in which the momentum is conserved but K.E is not conserved, is known as Inelastic collision. "
  In such type of collision, same type of the K.E is converted into internal energy, sound energy and the work needed to permanently deform the object involed, such as cars ina car crash.
  Example:
  1. Collision between two vehicles
  2. Collision between two mud balls

An object is thrown vertically upward.Discuss the sign of acceleration due to gravity, relative to velocity, while the object is in air.

• Ans 1: When the object is thrown vertically upward, it will move against the direction of gravity. The sign of acceleration due to gravity relative to velocity will be taken as negative. When the object is moving downward, the sign of acceleration due to gravity will be positive.

What is meant by perfectly elastic head-on-collision ?discuss the elastic collision in one dimension and find the mathematical equation for calculating the final velocities of colliding objects in one dimension?

• Ans 1: Perfectly elastic head-on-collision:The collision in which the motion of the objects occurs along a straight line is known as perfect elastic head-on-collision.Determination of mathematical equations for calculating the final velocities of colliding objects in one dimension:

Define the following terms?

Acceleration

Uniform Acceleration

Variable Acceleration

Radical Acceleration

Linear Acceleration

Positive Acceleration

Negative Acceleration

Instantaneous Acceleration

• Ans 1: Acceleration:The rate of change of velocity is known as acceleration.
  Mathematically, we have
  Acceleration = v/t It is a vector quantity. It SI unit m/sec²
  Dimensions of acceleration:We know that
  V= Displacement / time = m/sec= Length / Time
  V=[L T^-1]
  Dimensions of acceleration:We Known that
  a = Velocity/time = m/sec . sec = m/sec^-2
  a = Length/time² a = [L T^-2]
  Uniform Acceleration:A body is said to be moving with the uniform acceleration if equal change occurs in velocity in equal intervals of time.
  Variable Acceleration:A body is said to be moving with variable Acceleration if unequal change occurs in velocity in equal intervals intervals of time.
  Linear Acceleration:The acceleration which is produced due to change in magnitude of velocity is known as linear acceleration.
  Radical Acceleration:The acceleration which is produced due to change indirection of velocity is known as radical acceleration.
  Positive Acceleration:The acceleration is said to be positive if the magnitude of velocity increases with respect to time.
  Negative Acceleration:The acceleration will be magnitude of velocity decreases with respect to time.
  InstantaneousAcceleration:The acceleration of a body at any particular instant of time is known as instantaneous acceleration.

Write any two properties of inertial frame of reference.

• Ans 1:
  1. A non-accelerated frame of reference is an inertial frame of reference.
  2. Newton's 1st law of motion holds good in an inertial frame of reference.