PhysicsLAB: Energy Methods: Projectiles

Mechanical energies:

PE = mgh

KE = ½mv²

Conservation of Energy:

PE₁ + KE₁ = PE₂ + KE₂

Kinematics Equations for Uniformly Accelerated Motion:

You may use g = 10 m/sec² on this worksheet to ease your calculations.

Note: Energy methods will help you solve for resultant velocities and vertical displacements. Only kinematics will help you solve for time and horizontal displacements.

Refer to the following information for the next four questions.

A projectile is shot straight upwards with a speed of 20 m/sec.

Use energy methods to determine how high it will be when its speed is 10 m/sec.

Use energy methods to determine the maximum height that it will reach before it starts falling back towards its release position.

Can energy methods be used to determine how much time it takes to reach the apex?

YesNo

Calculate how much time it will take to reach the apex.

Refer to the following information for the next five questions.

A ball is tossed horizontally off a 6 meter balcony. It strikes the ground 4 meters from the base of the balcony.

Calculate how much time it will take to reach the ground.

How fast was the ball tossed from the balcony?

Use energy methods to determine how fast the ball was traveling when it was located 3 meters above the ground?

Use energy methods to determine how fast the ball initially strikes the ground.

At what angle does the ball impact with the ground?