Question

A car rounds a 75-m radius curve at a constant speed of 18 m/s. a ball is suspended by a string from the ceiling the car and moves with the car. the angle between the string and the vertical is:

Answer 1

The angle between the string and the vertical is computed by:
Centripetal acceleration Ac = V²/R = 18²/75 = 4.32 m/s² horizontal 
Gravitational acceleration g = 9.8 m/s² down 

Θ = arctan(Ac/g)
= arctan (4.32m/s^2 / 9.8 m/s^2)
= 23.79° is the answer.