Answer:
Data that we know:
Mass of the car = 950kg.
Gravitational acceleration = -9.8m/s^2.
Acceleration of the car = -1.2 m/s^2.
(the negative signs are because that accelerations point downwards)
Now, the total acceleration of the car is:
-1.2m/s^2 = -9.8m/s^2 + Ac.
Where Ac is the acceleration caused by the cable, that is opposite to the acceleration of the car:
Ac = 9.8m/s^2 - 1.2m/s^2 = 8.6m/s^2.
Now we have the accelerations, remember that by second's newton law we have:
F = m*a
Then the force of the cable is:
Fc = 8.6m/s^2*950kg = 8,170N.
The gravitational force is:
Fg = -9.8m/s^2*950kg = -9,310N
The net force is:
Ft = 8,170N - 9,310N = -1,140N.
Below is the free body-diagram.
