Chapter 9: Force and Motion

The SI unit of force is _______________

Which one among the following is not a type of non-contact forces?

• Muscular force

• Magnetic force

• Gravitational force

• Electrostatic force

The pressure exerted by a liquid ______ with depth.

friction is a _________ force

• Non contact

• Contact

• magnetic

• electrostatic

Friction always

• Helps in motion

• Opposes motion

• Both of these

• None of these

Which of the following produces least friction?

• Rolling Friction

• Sliding Friction

• Static Friction

Whenever the surfaces in contact tend to move with respect to each other , the force of friction comes into play

• only if one of the two objects is liquid

• only if the objects are solid

• only if one of the two objects is gas

• Irrespective of whether the objects are solid,liquid or gas.

The shape of an aeroplane is like a _______ to reduce the friction exerted by air.

• Tortoise

• Dog

• Cat

• Bird

Fluid friction will depend on

• shape of the moving object

• Viscosity of fluid

• speed of the object

• All of these

It is difficult to walk on an oily floor because

• Force of friction is very less

• Force of friction is very high

• we don't like to walk on oily floor

• None of these