# Science Forces and motion

## 17 terms

### Newton's first law of motion

An object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line, unless acted on by an unbalanced force.

### Inertia

The tendency of all objects to resist any change in motion.

### Newton's second law of motion

The acceleration of an object depends on the mass of the object and the amount of force applied to the object.

### The relationship between the force applied and the object's acceleration.

An objects acceleration increases as the force applied increases. (Vice versa.)

a=F/m or F=m x a

### Newton's third law of motion

Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first.

### How forces in each pair are related

When a force is exerted, another force occurs that's equal in size and opposite in direction.

### What Newton explained with his 3 laws of motion

He explained the relationship between force and the motion of an object.

### Newton's first law is sometimes called..

The Law of Inertia

### The direction in which objects accelerate

In the direction of the force applied.

### terminal velocity

When an object is falling at a constant velocity.

### Inertia

The tendency of an object to resist a change in motion.

### Projectile motion

The path that a thrown object follows.

### Free fall

When air resistance does not affect the motion of a falling object.

### When a soccer ball is kicked why do the reaction and action forces NOT cancel eachother out?

Because the forces act on different objects.

### An object is in projectile motion if it...

...is thrown with a horizontal push, is accelerated downward by gravity, and does not accelerate horizontally.

### The formula for momentum

p=m x v or momentum= mass x velocity