mechanics (mass, force, acceleration, work, energy, momentum, velocity) - Category wise Question and Answer Practice Test with Solutions

Question : 16 [PSC (Pre) 2016]

A man jumped at a speed of 5 metre per second from a stationary boat and the boat moved off with the speed of 0.5 metre per second. How many times is the mass of the boat greater than that of the man?

a) 2.5 times

b) 4.5 times

c) 5.5 times

d) 10 times

Question : 17 [BPSC (Pre) 2001]

Force is the product of

a) Weight and velocity

b) Mass and acceleration

c) Mass and velocity

d) Weight and acceleration

Question : 18

The force exerted by the floor of an elevator on the foot of a person standing there, is more than his weight, if the elevator is

a) going up and slowing down

b) going up and speeding up

c) going down and slowing down

d) either (a) or (b)

Question : 19 [IAS Prelim]

Assertion (A):
A man standing on a completely frictionless surface can propel himself by whistling.
Reason (R) :
If no external force acts on a system, its momentum cannot change.

a) A is true but R is false

b) Both A and R are true but R is not a correct explanation of A

c) Both A and R are true and R is the correct explanation of A

d) A is false but R is true

Question : 20 [CDS]

A gymnast takes turns with her arms & legs stretched. When she pulls her arms and legs

a) the angular velocity stays constant

b) the moment of inertia decreases

c) the angular velocity decreases

d) the angular momentum increases