Q2 of 21 Page 109

A truck of mass 500kg moving with constant speed 10ms–1. If sand is dropped into the truck at a constant rate 10kgmin–1, the force required to maintain the motion with constant velocity is

Given:

Mass of truck at t = 0 s is 500 kg


Constant velocity of truck = 10 ms–1


Change in mass with time




Force =






Since velocity is to be kept constant so,






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1

A constant force of 12 N acts on a body for 4 s. Find the change in the linear momentum of the body.

 3

Two blocks of masses 2kg and 4kg are hanging with the help of a massless string passing over an ideal pulley inside an elevator. The elevator is moving upward with an acceleration g/2. The tension in the string connected between the blocks will be (take g = 10 ms–2)

a) 40N


b) 60N


c) 80N


d) 20N

 4

Two identical small bodies each of mass m and charge q are suspended from two strings each of length l from a fixed point. The whole system is taken into an orbiting artificial satellite. Find the tension in strings

 5

A man of mass 60 kg is standing on a light weighing machine kept in a box of mass 30 kg. The box is hanging from a pulley fixed to the ceiling through a light rope the other end of which is held by the man himself. If he manages to keep the box at rest

(a) What is the weight shown by the machine?


(b) What force should the man exert on the rope to get his correct weight on the machine?