Question

A skateboarder is moving at a speed of 8.0 m/s when he begins to go up a frictionless ramp. When takes off the ramp he is moving at 5.5 m/s. How high is the ramp? KEi + PEi = KEf

Answer 1

Answer: 1.72 m

Step-by-step explanation:

KE i + PE i = KE f + PE f

PE i = 0 because the skater starts at the bottom of the ramp where h = 0

Even though mass is not given, we can still figure this out

1/2 mv2 + 0 = 1/2 mv2 + mgh:

Take m out of the formula, leaving:

1/2 v2 = 1/2 v2 + gh

8.0^2/2 = 5.5^2/2 + (9.8 m/s2)h

64/2 = 30.25/2 = (9.8 m/s2)h

solve for h:

h = (32 - 15.125) / 9.8 = 1.72 m