What is the net force on the car while it's coming to a stop? A car having a mass of 500 kg is initially traveling with a speed of 80 km/HR. It slows down at a constant rate, coming to a stop in a distance of 50 m.
A. -12.4x10^3 N B. 2.4x10^3 N C. -2.4x10^3 N D. None of the above.
The answer to this is C. The formula that you should follow for this is the amount of work that is done on your car is equal to KE. The formula for this is Fnetd. This will then be multiplied by 50 so that the proper answer will be given. The equation that you are going to use should be Fnet = -1.2 x 105J / 50 m = -2.4 x 103 N.
If you would encounter questions that are similar to this again, you will know how to answer them even if the numbers are going to be different as long as you know the formula. It is best that you know the formula for the different questions that will be provided.
The total work done on the car (the work done by the net force) equals the change in KE.
total work done on car = Fnetd = Fnet x 50 m
total work done on car = change in KE
-> Fnet = -1.2 x 105J / 50 m = -2.4 x 103 N