Page 12 - E book prim 4

Delta Modern Language Schools Unit (2) concept (1)
Science department
Grade 4
1st term 2024-2025

Starting and stopping

 The shockwave truck has been fitted with three jet engines, so that it is aboutfive
times faster than the normal truck.

There are two forces that cause objects to move which are:

- Pushing force.
- Pulling force.
 By increasing number of fire extinguishers, the released air makes the cartmoving

fast.
 If balanced forces act on an object, it will not move.
 If unbalanced forces act on an object, it will move towards the greater force.

Motion:

It is any change in the position of an object relative to a fixed point.

Gravity:

It is the force that pulls objects toward the center of the earth.

Force:

It is a push or pull that is applied to an object causes it to change its position.

Friction:

It is a force that is exerted when objects rub against each other.

 Friction force always slows down or stops motion of moving objects.
 The direction of friction is always opposite to the direction of motion of amoving

object.
 Hard push causes object to travel a long distance.
 Gentle push causes object to travel a small distance.

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