Newton's First & Second Law

What is Newton’s first law?

A resultant force is required to change the motion of an object,

This applies to stationary and moving objects,

What does it mean if the resultant force on a stationary object is 0?

The object remains stationary.

What happens if the resultant force of a moving object is 0?

It will carry on moving at the same velocity.

What is Newton’s second law?

If a resultant force that is not 0 acts on an object, then it will cause the object to accelerate.

What does it mean if the resultant force is to the right?

The right arrow is bigger than the left arrow.

The object will accelerate to the right.

If there is a resultant force to the right on a stationary object, what will happen?

It will start moving to the right.

If the resultant force was acting to the right on an object moving to the right, what would happen?

If it was already moving to the right, it would speed up.

If the resultant force was acting right on an object moving to the left, what would happen?

It would slow down, as it is acting in the opposite direction.

What can the acceleration just result in?

A change in direction, rather than a change in speed.

Acceleration is change in velocity/change in time. velocity has speed and direction.

What is circular motion?

e.g. movement of the moon around the earth.

Although speed of the moon remains constant, we still say it is accelerating, because its direction is always changing slightly. This is because of the gravitational pull on the moon which acts perpendicular to the moon’s motion.