Question

A coin is placed on a vinyl stereo record making 33 1/3 revolutions per minute.

a. In what direction is the acceleration of the coin?

b.Find the magnitude of the acceleration when the coin is placed 5.0, 10.0, and 15.0 cm from the center of the record.

c. What force accelerates the coin?

d.In which of the three radii listed in b would the coin be most likely to fly off? Why?

Answer 1

a. In what direction is the acceleration of the coin?

The acceleration is toward the center of the record.

b.Find the magnitude of the acceleration when the coin is placed 5.0, 10.0, and 15.0 cm from the center of the record.

T = 1 / f = 1 / (33.1/3min) = (0.0300 min)(60s/ 1min) = 1.8s

r = 5.0 cm: a_c = 4?² r / T² = 4?².(0,05m) / (1,8s)² = 0.61 m/s²

r = 10.0 cm: a_c = 4?² r / T² = 4?².(0,100m) / (1,8s)² =1.22 m/s²

r = 15.0 cm: a_c = 4?² r / T² = 4?².(0,15m) / (1,8s)² = 1.83 m/s²

c. What force accelerates the coin?

frictional force between coin and record

d.In which of the three radii listed in b would the coin be most likely to fly off? Why?

15 cm

The largest radius because force needed to hold it is the greatest.