Conservation of Energy – Practice!
𝐸𝑖 = 𝐸𝑓
𝑃𝐸𝑖 + 𝐾𝐸𝑖 = 𝑃𝐸𝑓 + 𝐾𝐸𝑓
1. If I drop a penny (mass = 2.5g) off the top the CN tower (which has a height of 457m)
a. What is its gravitational potential energy?
b. What is its kinetic energy at the instant before it touches the ground?
c. What is its speed at the instant before it touches the ground?
2. A 5kg object is dropped and reaches the floor at a speed of 3.2 m/s.
a. What is its kinetic energy when it reaches the floor?
b. What was its potential energy before it was dropped?
c. What height was it dropped from?