Projectile Motion

Question 1

What shape is the trajectory of a ball thrown?

Answer 1

Parabolic curve

Question 2

If one ball is thrown off a building at the same time another identical ball is dropped of the same building, which will hit the ground first?

Answer 2

They will hit the ground at the same time.

Question 3

Why would they hit the ground at the same time?

Answer 3

The horizontal velocity of the ball being thrown is at a constant speed so there is no horizontal force(ignoring air resistance) and the vertical velocity of both balls accelerates at the same rate due to gravity.

Question 4

What was Newton’s suggestion of horizontal projection?

Answer 4

If a ball could be kicked hard enough off a cliff it would never reach the ground but stay in orbit as gravity would make the ball fall to Earth but never reach it because of the Earth’s curvature.

Question 5

What are the basic laws of throwing a ball?

Answer 5

• It decelerates as it goes up
• The horizontal speed is constant
• It accelerates as it comes down
• The only force on the ball is vertical due to gravity
• F = ma