PHYSICS [1 Mark Question Answer]

Two kinds of forces in nature are :

1. Contact forces
2. Non-contact forces

There is change in size and shape of spring.

The speed of the moving cycle is slowed down.

The direction of the ball changes.

The heavy cart begins to move.

The shape and size of catapult changes i.e., its length increases

On stretching a rubber string, its length increases.

A player kicks a moving football to change its direction of motion.

The speed of a moving vehicle is slowed down by applying the brakes.

A moving bicycle is stopped by applying the brakes.

A car originally at rest when pushed, begins to move.

When a force is applied to a body that is not free to move, it gets deformed i. e., the shape or size of the body changes.

When a force is applied to a moving body, it can be made to stop or it can change the direction of motion.

When a force is applied on a stationary body, it begins to move.

Force is a physical cause that changes or may tend to change the state of rest or the state of motion of an object. The S.I. unit of force is Newton.

Static friction > Sliding friction > Rolling friction.

The minimum force required to roll a body on a surface is called the force of rolling friction.

The maximum force exerted by a surface on a body so long as it remains stationary is called the force of static friction.

When the road becomes wet after rain, friction is reduced, and hence, the road becomes slippery.

When the hands are oily, then the oil acts as a lubricant and reduces the friction.
As the friction force is less, it is difficult to get a grip of the inkpot and it becomes difficult to open it.

Change in shape of a sponge on squeezing.

Stretching a rubber string.

The eraser gets smaller and smaller as we use it more and more due to frictional force causing wear and tear of the eraser.

To move a grass roller on a lawn, it is pulled by a gardener.

It is due to friction between the brakes and the rim of the wheel that it becomes hot.

To open a door, we push it.

Friction is of three kinds:

1. Static friction
2. Sliding friction,
3. Rolling friction

Wooden surface offers to move friction on a body.

When the truck is loaded there will be more friction between the truck and the road.

Two factors which directly affect the force of friction are:

1. The smoothness of the surface.
2. The presence of solid, liquid, or gas around the moving body.

The cause of friction is the interlocking of the irregular projections on the two surfaces in contact.

If we stop paddling our bicycle, it gradually slows down and ultimately it stops after traveling a certain distance. This is due to the frictional force between bicycle and ground.

Friction is that force that opposes the relative motion between the two surfaces that are in contact with each other.

The weight of the body is the force with which the earth attracts it towards the centre. It depends on acceleration due to gravity.

Muscular force

Gravitational force

Muscular force

Magnetic force

Muscular force

Force of tension.

Electrostatic force

Gravitational force.

Frictional force

Muscular force

Force

Gravitational force exerted by the earth is very strong. This force attracts all objects on earth towards its centre. That is why all objects on earth have a tendency to fall towards the centre of the earth.

It is due to the electrostatic force between the balloon and the wall. Opposite charges attract each other.

It two equal forces act on an object in the opposite direction, they balance out each other and the object does not move in any direction.

A push or pull acting upon an object as a result of its interaction with another object is called force. Its SI unit is the newton (N).

Due to frictional force acting on it which resists/opposes the motion of the object.