Physics problem on forces, already have answer just need explanation as I don't quite understand?

Question

Calculate the average force that must act upon a car to cause it to accelerate from rest to 16 m/s in 6.6s if the mass of the car is 1700kg. In my last question someone answered and I got the answer but don't quite understand why they used the formula V^2=V0^2+2at. If someone could explain this to me it would be much appreciated, thank you

Answer 1

There is a formula, V^2 = V0^2 + 2ax, not 2at, which is used when you are dealing with the acceleration and the distance traveled. In this case, you can use the simpler formula a = ΔV/Δt, where the Greek letter Δ represents the change in a quantity. An acceleration from 0 to 16 m/s in 6.6 s is an acceleration of (16 m/s) / (6.6 s) = 2.42 m/s^2. Force is the product of mass and acceleration, so F = ma = (1700 kg)(2.42 m/s^2) = 4121 N.

Answer 2

The cause of the dispute between your 1st 2 answers is round-off error. I would go with your first answer.



F = m*a = m * Δv / Δt = 1700 kg * 16 m/s / 6.6 s = 4121 kg.m/s^2 = 4121 N

Answer 3

Acceleration = (v/t) = 16/6.6, = 2.4242(r) m/sec^2.

Force = (mass x acceleration) = 4,121.21 Newtons.

Answer 4

DavidK93's idea is RIGHT. Only thing is he had inaccurate result when multiplying. It is not 4121 N BUT it is 4114 N