You and a friend are sitting on skateboards on the top of a hill. You are in fro
ID: 1359800 • Letter: Y
Question
You and a friend are sitting on skateboards on the top of a hill. You are in front of your friend and your friend holds onto you from behind. The hill has a 20% grade to it. The coefficient of rolling friction for you is r = 0.2 and the coefficient of rolling friction for your friend is r = 0.15. You have a mass of mA = 80 kg whereas your friend’s mass is mB = 100 kg. (a) How long does it take for the two of you to roll 50 m down the hill? (b) How fast are you traveling when you reach the bottom of the hill?
Explanation / Answer
hill has a 20% grade to it
SLOPE =1/5
tan(theta) =1/5
coefficient of rolling friction for you is r = 0.2 and the coefficient of rolling friction for your friend is r = 0.15.
2 xtheta x a =w22-w12
a = Urg +Urg = 0.35 x 9.8 =3.43rad/s2
theta =wt +(1/2)at2
50 = (1/2) x 3.42 x t2
t =5.4 sec
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.