Physics car over bump in road find apparent weight.?

Question

Driving in your car with a constant speed of 12 m/s, you encounter a bump in the road that has a circular cross section. If the radius of curvature of the bump is r = 31 m, find the apparent weight of a 65 kg person in your car as you pass over the top of the bump.

Answer 1

at the top of the bump
centripetal accelaration upwards and g downwards
a = v^2/r = 144/31
m = 65 kg
w = 65 *9.8
w' = 65 * [9.8 - 144/31] = [9.8 - 4.645]*65 = 5.155*65 =
332 newton approx
Apparent mass is approx 34 kg

Answer 2

As you pass over the bump, the folks in the car feel a centrifugal accleration v^2 / r in the upward direction.

Add (or rather subtract) that from g, the acceleration from the earth's gravity, which is down.

The apparent weight is the total acceleration times the person's mass.

Edit: re above answer--correct mostly, but be careful of your terminology:

Centrifugal acceleration is the upward acceleration felt by the folks in the car--a non-inertial reference frame.

Centripetal acceleration is the net downward acceleration noted by an observer outside the car (inertial ref frame). This net acceleration is what keeps the car and the folks in it on a circular path.

The easier one to use in this problem is centrifugal (which is what the answerer did by positing an upward force, although he called it the wrong thing).

One other terminology mistake--never talk about an apparent mass like that--that doesn't mean what you want it to mean. Mass is inertia, which is constant (classically). It is okay, though, to talk about apparent weight, which is the true weight plus (or minus) the contribution from the centrigugal force.