Help with the second one please!?

Question

A car is traveling around a circular racing course. The car travels from rest and gradually climbs to a max velocity of 140 m/s. Given the radius of the track is 100 meters and the car goes around the track 2 times. What is the acceleration of the car? *

If the mass of the car is 1200 kg. What is the magnitude of the force acting on the car? *

16800 N

18726 N

9363 N

12000 N

Answer 1

I agree with Daniel, but I tried using the linear relationship only and got 9363. I used the kinematic equation:

Vf squared = Vi squared + 2atimes delta x Delta x is 2 times the circumference = 4pi * r the linear a becomes

Vf squared/(2*4*pi*100). using pi = 3.14 gave ans = 9363.05

Answer 2

I find this question a little tricky, because the car is under two forces --

the centripetal force and the forward force.

However, accounting for the centripetal force gives a result not matching any of the

given options.

So I assume that you are supposed to ignore the centripetal force.

Given that you are asking for help with the force only, I assume you successfully

calculated the acceleration.

Once you have that, you can calculate the force by Newton's second law:

F = ma