REVISION of Force and Pressure and Friction

Which of the following forces is needed to pick up your school bag?

• Muscular force

• Gravitational force

• Magnetic force

• Electrostatic force

When a ball is dropped from a certain height the speed of the ball goes on increasing due to

• Gravitational force

• Biological force

• Magnetic force

• all of these

Friction can be increased by

• making the surface smooth

• lubricating the surfaces

• using ball bearing

• making the surface rough

When the applied force doubled, then friction becomes

• doubled

• halved

• quadrupled

• zero

On which of the following parameters, force of friction depends

• mass of body

• nature of the surfaces

• both a and b

• none of these

Which of the following one is a right arrangement

• rolling friction> static friction> sliding friction

• sliding friction< static friction< rolling friction

• rolling friction> static friction> sliding friction

• static friction> rolling friction<sliding friction

A body is moving on a rough horizontal surface towards north. then the direction of frictional force is towards

• east

• west

• north

• south

If no external force acts on a body, it will

• move with more speed

• change its shape

• break into pieces

• either remain in its state of rest or uniform motion

______ is a measure of the gravitational force acting on an object

• mass

• weight

• pressure

• none of these

Mass differs from weight because

• weight is a force whereas and mass is not a force

• the mass of an object is always more than its weight

• mass can be expressed only in the metric system

• there is no difference