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

Question : 26

When a satellite is in the synchronous orbit above the equator, it stays in one place with reference to the earth by making each revolution in just the same time as it takes the earth to rotate once. What is the altitude of the synchronous orbit?

a) 32500 km

b) 30000 km

c) 20000 km

d) 36000 km

Question : 27

Two satellites of earth, S₁ and S₂ are moving in the same orbit. The mass of S₁ is four times the mass of S₂ . Which one of the following statements is true?

a) The kinetic energy of the two satellites are equal.

b) S₁ and S₂ are moving with the same speed.

c) The potential energies of earth satellites in the two cases are equal.

d) The time period of S₁ is four times that of S₂

Question : 28 [IAS (Pre) 1996]

A simple machine helps a person in doing

a) The same amount of work slowly

b) The same amount of work with lesser force

c) Less work

d) The same amount of work much faster

Question : 29 [PSC (Pre) 2018]

Consider the following statement and conclusions which can be drawn from it. Choose the correct conclusion.
Statement: In starting a loaded cart, one has to push harder than to keep it moving.

a) There is less friction once the cart starts moving

b) The wheels tend to slip initially

c) The weight of a moving object is less

d) Practice makes perfect

Question : 30

Consider an elevator moving downwards with an acceleration a, the force exerted by a passenger of mass m on the floor of the elevator is

a) mg – ma

b) ma – mg

c) ma

d) mg + ma