# Physics equations/06-Uniform Circular Motion and Gravitation/Q:friction

## practice quiz

1 A merry-go-round has an angular frequency, $\omega$ , equal to 0.15 rad/sec. How many minutes does it take to complete 8.5 revolutions?

 a) 4.49 minutes. b) 5.16 minutes. c) 5.93 minutes. d) 6.82 minutes. e) 7.85 minutes.

2 A merry-go round has a period of 0.22 minutes. What is the centripetal force on a 81.2 kg person who is standing 1.64 meters from the center?

 a) 26.2 newtons. b) 30.2 newtons. c) 34.7 newtons. d) 39.9 newtons. e) 45.9 newtons.

3 A merry-go round has a period of 0.22 minutes. What is the minimum coefficient of static friction that would allow a 81.2 kg person to stand1.64 meters from the center, without grabbing something?

 a) 0.033 b) 0.038 c) 0.044 d) 0.05 e) 0.058

4 What is the gravitational acceleration on a plant that is 2.37 times more massive than Earth, and a radius that is 1.52 times greater than Earths?

 a) 10.1 m/s2 b) 11.6 m/s2 c) 13.3 m/s2 d) 15.3 m/s2 e) 17.6 m/s2

5 What is the gravitational acceleration on a plant that is 2.89 times more dense than Earth, and a radius that is 2.38 times greater than Earth's?

 a) 58.6 m/s2 b) 67.4 m/s2 c) 77.5 m/s2 d) 89.1 m/s2 e) 102.5 m/s2