A car moving at 10.0 m/s encounters a bump that has a circular cross-section with a radius of 30.0 m. What is the normal force exerted by the seat of the car on a 60.0-kg passenger when the car is at the top of the bump?
A) 200 N
B) 389 N
C) 789 N
D) 489 N
E) 589 N

Question

Quizplus · Accepted Answer

At the top of the bump, the car will experience a centrifugal force directed away from the center of the circular bump. At this point, the normal force exerted by the seat of the car on the passenger must equal the passenger's weight plus the centrifugal force. 
Therefore, the normal force N = mg + mv^2/r, where m = 60.0 kg, g = 9.81 m/s^2, v = 10.0 m/s, and r = 30.0 m. 
Plugging in the values: N = (60.0 kg)(9.81 m/s^2) + (60.0 kg)(10.0 m/s)^2 /(30.0 m) = 589 N. 
Therefore, the best choice is B.

A Car Moving at 10