Question

A car with a mass of 950 kg is tied to a crane by a strong cable and being lowered at a rate of 1.2 m/s2. Draw a free-body diagram showing all the forces acting on the car. Include the values of each force. Show all calculations.

Answer 1

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.