Force needed to slow a car from 35 mph to 5 mph?

Answer 1

The most likely equation you would use would be Newton's 2nd Law of Motion. Namely:
Force = mass X acceleration

This is impossible to answer. You would need to know the mass of the car in order to figure out a necessary stopping force.

Also, you need to know over how long a time frame the change in speed happened over to calculate the negative acceleration.

For example, the force required to slow a 1 000 kg car from 35 to 5 mph (about 15.6 m/s to 2.2 m/s) in 5 seconds would be found like this:

Force = 1 000 kg X [(15.6-2.2 m/s)/ 5 s]

Force = 1 000 kg X (13.4 m/s / 5 s)

Force = 1 000 kg X 2.68 m/s2

Force = 2 680 kg m/s2

Force = 2 680 Newtons in the direction opposite to the travel of the car.

Answer 2

The force needed to slow a car from 35 mph to 5 mph will depend on several factors, including the mass of the car, the braking system efficiency, and the coefficient of friction between the tires and the road. In general, a greater force will be required to decelerate a heavier car or if the road conditions are slippery. It is important to note that the force needed can be calculated using the car's final velocity, initial velocity, and the distance over which the car decelerates.