Mini-Unit 2- Projectile Motion

Question 1

What is a projectile? (examples)

Answer 1

An object moving through the air and accelerating due to gravity.

Assuming air resistance is negligible this includes:
- An object dropped from rest or thrown downwards
- An object thrown upwards or at an angle above the horizon
- An object launched horizontally

Question 2

What is the only force acting on a projectile?

Answer 2

Gravity

Question 3

What is special about x and y components?

Answer 3

They are perpendicular and therefore totally independent.

Question 4

Why is the horizontal motion of a projectile constant?

Answer 4

There is no net force acting on the projectile in the x.

Question 5

Explain why a baseball dropped from a particular height and a cannonball fired at 20 m/s horizontally from that same height will land at the same time.

Answer 5

An objects horizontal motion will have absolutely no affect on its vertical motion and vice versa. This is because x and y components are perpendicular and therefore totally independent of each other. While the baseball and the cannonball have very different initial horizontal velocities, they both have a vi of 0 in the y and the only force responsible for their acceleration is gravity. Since their y components are the same they will land at the same time.