A lift is going up. The total mass of the lift and the passengers is 1500kg. The variation in the speed of the lift is given by the graph as shown in Fig.
. What will be the average acceleration during the course of the entire motion ?

Two stones are thrown up simultaneously from the edge of a cliff 200 m high with initial speeds of 15 m s^-1 and 30 m s^-1 . Verify that the graph shown in Fig. 3.27 correctly represents the time variation of the relative position of the second stone with respect to the first. Neglect air resistance and assume that the stones do not rebound after hitting the ground. Take g = 10 m s^-2 . Give the equations for the linear and curved parts of the plot.

The fig shows the position the position- time graph of a particle of mass 4 kg. What is the Impulse at t = 0 and t = 4 s : (consider one-dimensional motion only).

In the figure gives a speed-time graph of a particle in motion along a constant direction. Three equal intervals of time are shwon. In which interval is the average acceleration greatest in magnitude ? In which interval is the average speed greatest ? Choosing the positive direction as the constant direction of motion, give the signs of v and a in the three intervals. What are the acceleration at the points A,B,C and D?

An elevator of total mass (elevator+ passenger) 3600 kg in moving up with a constant speed of 2 ms^-1 . A frictional force of 1300 M opposes its motion. Determine the minimum power delivered by the motor to the elevator.

A man weighs 80 kg. He stands on a weighing scale in the lift, which is moving upward with a uniform acceleration of 5 ms^-2 what whould be the reading on the scale? (g = 10 m//s^2) .

A hydraulic automobile lift is designed to lift cars with a maximum mass of 3000 kg. The area of cross-section of the piston carrying the load is 425 cm^2 . What maximum pressure would the smaller piston have to bear ?

A man of mass 70 kg stands on a weighing scale in a lift which is moving :- upwards with a uniform acceleration of 5 m s^-2 . What would be the readings on the scale in each case?

A man of mass 60 kg stands on a weighing machine in a lift which is moving downwards with a uniform acceleration 2 m s^-2 . What would be the reading of machine?

A block of mass 25 kg is raised by a 50 kg man in two different ways as shown in Fig. 5.19. What is the action on the floor by the man in the two cases ? If the floor yields to a normal force of 700 N, which mode should the man adopt to lift the block without the floor yielding ?