The terminal velocity of a 2 cm radius ball in liquid is 20 cms-1. What would be the terminal velocity if the radius of the ball were halved? Keeping the mass constant
The spectrum of a star’s light is measured and the wavelength of one of the lines as thesodium’s line is found
to be 589 nm. The same line has the wavelength of 497 nm whenobserved in the laboratory. This means the
star is
The force exerted by the fluid in a hydraulic pump on the piston is 2000 N.If the area of the piston is 10 cm2 the fluid pressure on the piston is in N/cm2
A bullet of mass 10 g hits a target and penetrates 2 cm into it.If the average friction offered by the target is 100 N,then the velocity with which the bullet hits the target is
The excess (equal in number) of electrons that must be placed on each of two small spheres spaced 3 cm apart,with force of repulsion between the spheres to be 10-19 N,is
A liquid flows through a pipe of non-uniform cross-section. If A1 and A2 are the cross-section of the portions of the pipe at two points the ratio of velocities of liquid at these points will be
A boy walks uniformly along the sides of a rectangular park of size 400 m x 300 m.starting from one corner to the other corner diagonally opposite.Which of the following statements is incorrect?
A whistle is revolved with high speed in a horizontal circle of radius R. to an observer at the centre of the circle the frequency of the whistle will appear to be:
A particle is moving along a circular path of radius 5 m with uniform speed 5 m/sec what will be the magnitude of centripetal acceleration when the particle completes half revolution
The cables holding a passenger lift swap and lift falls freely towards the ground. A person inside the lift is standing on a weighing machine. What does he notice?
A uniform plank of weigth 20 N is 200 cm long and rests on a support that is 60 cm from one end At what distance from that end must an 80 N weight be placed in order to balance the plank
