Kinetics of particles

State which of the following statements is false:

• A force is required to move a body at rest
• A force is required to keep a body moving with uniform velocity
• A force is required to change the direction of motion of a body moving with uniform velocity
• A force is required to accelerate a body moving with uniform velocity

The physical quantity, which is a measure of inertia, is

• Mass
• velocity
• acceleration
• force

What is the inclination of a smooth inclined plane such that the accelerating force acting on a block sliding down it may be g/2?

• 30°
• 45°
• 60°
• 75°

The acceleration of a block sliding down an inclined plane is

• same as acceleration due to gravity
• less than acceleration due to gravity
• greater than acceleration due to gravity
• uniformly increasing

Two blocks A and B such that WA > WB slide down an inclined plane at the same time. If the coefficient of friction is same for both then which of the following statements is true?

• Acceleration of A is greater than acceleration of B.
• Acceleration of A is lesser than acceleration of B.
• Both the accelerations are equal
• Their accelerations are equal to acceleration due to gravity.

When a lift is accelerating up, the weight of a man standing on the floor of the lift is

• same as that when on ground
• greater than that on ground
• less than that on ground
• zero

When a lift is decelerating while moving upwards, what happens to the weight of a man standing on the floor of the lift?

• same as that when on ground

• greater than that on ground

• less than that on ground

• zero

When a lift is accelerating downwards, the weight of a man standing on the floor of the lift is

• same as that when on ground
• greater than that on ground
• less than that on ground
• zero

If a lift is decelerating while moving downwards then the weight of a man standing on the floor is

• same as that when on ground
• greater than that on ground
• less than that on ground
• zero

When a lift is freely falling, the reaction exerted by the floor of the lift on a man standing on the floor is

• same as that when on ground
• greater than that on ground
• less than that on ground
• zero