Question
A golf ball rolls off a cliff horizontally with a speed of 20.0 m/s. The cliff is a vertical distance of 13.2 meters above the surface of a lake below. Find how long the ball is in the air. 1.64 s
What is the impact speed of the ball just as it reaches the surface of the water?
What is the impact speed of the ball just as it reaches the surface of the water?
Answers
Anonymous
Forget the horizontal problem.
Do the vertical problem
It just falls 13.2 meters
a = g = -9.81 m/s^2
v = 0 - 9.81 t
h = 13.2 + 0 - 4.9 t^2
at ground h = 0
4.9 t^2 = 13.2
t = 1.64 seconds to fall 13.2 meters
v = -9.81 * 1.64 = - 16.1 m/s so speed is 16 m/s at crash
Do the vertical problem
It just falls 13.2 meters
a = g = -9.81 m/s^2
v = 0 - 9.81 t
h = 13.2 + 0 - 4.9 t^2
at ground h = 0
4.9 t^2 = 13.2
t = 1.64 seconds to fall 13.2 meters
v = -9.81 * 1.64 = - 16.1 m/s so speed is 16 m/s at crash