Laws of Motion

A force can change :

• the size or shape of a body

• the state of rest or of motion of a body

• the dimensions of a body

• All of the above.

Which of the following is a contact force —

• electrostatic force

• gravitational force

• frictional force

• magnetic force

The non-contact force is —

• force of reaction

• force due to gravity

• tension in string

• force of the friction

A ball placed on a table starts rolling down when the table is tilted. This is an example of :

• contact force

• non-contact force

• both (a) and (b)

• none of these

When a comb is rubbed on dry hair, it gets charged. This is an example of :

• Gravitational force

• normal reaction force

• magnetic force

• electrostatic force

The nature of gravitational force is always:

• repulsive

• attractive

• depends on the bodies involved

• None of the above

The magnitude of a non-contact force between two bodies ............... with an increase in their separation and ............... with a decrease in their separation.

• increases, decreases

• decreases, increases

• increases, increases

• decreases, decreases

On double the separation between two bodies the magnitude of the non-contact force between them becomes :

• one-eighth

• one-half

• one-fourth

• remains the same

A spring balance works on the principle of :

• gravitational force

• magnetic force

• restoring elastic force

• frictional force

Newton's first law includes:

• the definition of inertia

• the definition of force

• both the definition of inertia and the definition of force

• none of the above