Matric Part 1/9th Class Physics Chapter 4 Long Question With Answer for Unit 4 Turning Effect of Forces

9th Class Physics chapter 4 Long Questions

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Physics (New Book) - 9th Class Physics Chapter 4 Long Question Preparation

Question # 1

Q no:6(B) The steering of a has a radius 16 cm. Find the torque produced by a couple of 50 N.

Ans 1:
F = 50 N
r= 16 cm
d= AB = 32cm =0.32m
t=?
As we know that
t = Fx AB
t = 50 x 0.32
t = 16Nm

Question # 3

Write and explain the states of equilibrium

Ans 1: States of equilibrium: there are three states of equilibriumStable equilibrium ,Unstable equilibrium, Neutral equilibrium
Ans 2: Stable equilibrium: a body is said to be in stable equilibrium if after a slight tilt it returns to its previous positionExplanation: when a body is in stable equilibrium its center of gravity is at the lowest position. When it is tilted, its center of gravity rises. It returns to its state of sable equilibrium by lowering its center of gravity. Note that a body remains in state o stable equilibrium as long as the center of gravity acts through the base of the bodyExample: consider a block. when the block is tilt its entre of gravity G rises passes through its base in the tilt position. the block returns to its previous position. If the vertical line through G gets out of its base . the block does not return to its previous position. That is why a vehicle is made heavy at its bottom to keep its center of gravity as low as possible. A low center of gravity keep it stable. Moreover , the base of a vehicle is made wide so that the vertical line passing through its center of gravity should not get out of its base during a turn
Ans 3: Unstable equilibrium; if a body does not return to its previous position when et free after slightest till is said to b in unstable equilibriumExplanation: in state of unstable equilibrium C.G is at is highest position. Try to keep a pencil in vertical position on its top. whenever we leave it the pencil will topple over its top and hence fall down. Because of its center of gravity becomes lower and its weight acts out of its base. So the pencil is in the unstable equilibrium
Ans 4: Neutral equilibrium: if a body remains in its new position when disturbed from its previous position, it is said to be in state of neutral equilibriumExplanation: in neutral equilibrium C.G of the body remains at the same height . When a ball is placed on a horizontal surface and after displacing it the ball attains a new position and does not return but in both the positions its center of gravity remains at the same level . So a ball on a horizontal surface is in neutral equilibrium.

Question # 8

Discuss torque or moment of force

Ans 1: Before discussing torque we need some terms to define first.Rigid body: a body is composed of large numbver of small particles. If the distance between all paisrs of particles of the body do not change by applting all pairs of particles of the body don not change by applying a force . then it is called a righid bodyAxis of rotation: when a rigid body rotate s its particles also rottate in specific circle. The line joininig the centres of therse circles is called axis of rotatioinORThe line passes through the body and body can rotate aroun it. This line is called axis of rotation
Ans 2: Torque: turning effect of a force is called torque or moment of force .Example: force that produces turning effects are very common. Turning a pencil in a sharpener, turning a door knob etcDependence of torque: torque depends on two thingshow much force is appliedwhere the force is applied( moment arm)
Ans 3: Force: if we apply more force on a body to turn it the torque produced will also be more . Less force produces less amount of torqueExample : when someone press the pedal of bicycle applying slighter force . it will move slowly. But on the other hand more force on the pedals will produce more torque and hence speed will be more .
Ans 4: Where the force is applied: the location of force is also important. force at the door knob can easily open the door but the same force near the hinge o the door cannot open the doorMoment arm: the perpendicular distance between the axis of rotation and line of action of the force is called moment arm.
Ans 5: Line of action of force: a line along which a force acts is called the line of action of forceExplanation; the product of force F and moment arm L is called torqueUnit of torque; unit of torque is newton meterQuantity: it is a vector quantity.Unit of torque: a toque of 1 Nm is produced by a force of 1 newton acting perpendicular to the moment arm of 1m long

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Prepare Complete Set Wise Questions For Chapter 4 "9th Class Physics Chapter 4 Long Question Preparation "

Set 1

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9th Class Physics Chapter 4 Long Question Preparation - Set 1

Question # 1

Q no:6(B) The steering of a has a radius 16 cm. Find the torque produced by a couple of 50 N.

Ans 1:
F = 50 N
r= 16 cm
d= AB = 32cm =0.32m
t=?
As we know that
t = Fx AB
t = 50 x 0.32
t = 16Nm

Question # 3

Write and explain the states of equilibrium

Ans 1: States of equilibrium: there are three states of equilibriumStable equilibrium ,Unstable equilibrium, Neutral equilibrium
Ans 2: Stable equilibrium: a body is said to be in stable equilibrium if after a slight tilt it returns to its previous positionExplanation: when a body is in stable equilibrium its center of gravity is at the lowest position. When it is tilted, its center of gravity rises. It returns to its state of sable equilibrium by lowering its center of gravity. Note that a body remains in state o stable equilibrium as long as the center of gravity acts through the base of the bodyExample: consider a block. when the block is tilt its entre of gravity G rises passes through its base in the tilt position. the block returns to its previous position. If the vertical line through G gets out of its base . the block does not return to its previous position. That is why a vehicle is made heavy at its bottom to keep its center of gravity as low as possible. A low center of gravity keep it stable. Moreover , the base of a vehicle is made wide so that the vertical line passing through its center of gravity should not get out of its base during a turn
Ans 3: Unstable equilibrium; if a body does not return to its previous position when et free after slightest till is said to b in unstable equilibriumExplanation: in state of unstable equilibrium C.G is at is highest position. Try to keep a pencil in vertical position on its top. whenever we leave it the pencil will topple over its top and hence fall down. Because of its center of gravity becomes lower and its weight acts out of its base. So the pencil is in the unstable equilibrium
Ans 4: Neutral equilibrium: if a body remains in its new position when disturbed from its previous position, it is said to be in state of neutral equilibriumExplanation: in neutral equilibrium C.G of the body remains at the same height . When a ball is placed on a horizontal surface and after displacing it the ball attains a new position and does not return but in both the positions its center of gravity remains at the same level . So a ball on a horizontal surface is in neutral equilibrium.

Question # 8

Discuss torque or moment of force

Ans 1: Before discussing torque we need some terms to define first.Rigid body: a body is composed of large numbver of small particles. If the distance between all paisrs of particles of the body do not change by applting all pairs of particles of the body don not change by applying a force . then it is called a righid bodyAxis of rotation: when a rigid body rotate s its particles also rottate in specific circle. The line joininig the centres of therse circles is called axis of rotatioinORThe line passes through the body and body can rotate aroun it. This line is called axis of rotation
Ans 2: Torque: turning effect of a force is called torque or moment of force .Example: force that produces turning effects are very common. Turning a pencil in a sharpener, turning a door knob etcDependence of torque: torque depends on two thingshow much force is appliedwhere the force is applied( moment arm)
Ans 3: Force: if we apply more force on a body to turn it the torque produced will also be more . Less force produces less amount of torqueExample : when someone press the pedal of bicycle applying slighter force . it will move slowly. But on the other hand more force on the pedals will produce more torque and hence speed will be more .
Ans 4: Where the force is applied: the location of force is also important. force at the door knob can easily open the door but the same force near the hinge o the door cannot open the doorMoment arm: the perpendicular distance between the axis of rotation and line of action of the force is called moment arm.
Ans 5: Line of action of force: a line along which a force acts is called the line of action of forceExplanation; the product of force F and moment arm L is called torqueUnit of torque; unit of torque is newton meterQuantity: it is a vector quantity.Unit of torque: a toque of 1 Nm is produced by a force of 1 newton acting perpendicular to the moment arm of 1m long

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9th class Physics Chapter 4 Long Q's (English Medium)

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Matric Part 1/9th Class Physics Chapter 4 Long Question With Answer for Unit 4 Turning Effect of Forces

9th Class English Medium Subjects

9th Class Urdu Medium Subjects

Online Long Questions For Chapter 4 "9th Class Physics Chapter 4 Long Question Preparation "

Physics (New Book) - 9th Class Physics Chapter 4 Long Question Preparation

Q no:6(B) The steering of a has a radius 16 cm. Find the torque produced by a couple of 50 N.

A mechanic tightens the nut of a bicycle using a 15 cm long spannerby exerting a force of 200 N. Find the torque has tightened it.

Write and explain the states of equilibrium

Q no: 7 (B) A force is acting on a body making an angle of 30 with the horizontal. The horizontal component of the forceis 20 N. Find the force.

How we determine the center of gravity of an irregular shaped thin lamina

Discuss briefly addition of forces

Explain principle of moments

Discuss torque or moment of force

Q no: 7(A) Define parallel forces. Also explain its types or what is the difference between Like and Unlike parallel forces?

Q no: 5 (A) What is meant by torque or moment of a force ? Explain the factors on which it depend

Prepare Complete Set Wise Questions For Chapter 4 "9th Class Physics Chapter 4 Long Question Preparation "

Set 1

9th Class Physics Chapter 4 Long Question Preparation - Set 1

Q no:6(B) The steering of a has a radius 16 cm. Find the torque produced by a couple of 50 N.

A mechanic tightens the nut of a bicycle using a 15 cm long spannerby exerting a force of 200 N. Find the torque has tightened it.

Write and explain the states of equilibrium

Q no: 7 (B) A force is acting on a body making an angle of 30 with the horizontal. The horizontal component of the forceis 20 N. Find the force.

How we determine the center of gravity of an irregular shaped thin lamina

Discuss briefly addition of forces

Explain principle of moments

Discuss torque or moment of force

Q no: 7(A) Define parallel forces. Also explain its types or what is the difference between Like and Unlike parallel forces?

Q no: 5 (A) What is meant by torque or moment of a force ? Explain the factors on which it depend

9th class Physics Chapter 4 Long Q's (English Medium)

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