Work Energy Theorem

Question

How much force does a car engine exert to change the speed of a 1039 kg car from 14 m/s to 23 m/s in s distance of 595 m

Answer 1

The speed of the car determines the kinetic energy, which is 1/2 * m * v²

m = mass in kg

v = velocity in m/s

f = force in newtons, defined as kg*m/sec²

E (energy) is kg*m²/sec² = Newton-meters (N-m)

Energy change: ΔE = 1039kg * ((23m/s)² - (14m/s)²) = 3.46E5 N-m

For the force of the engine accelerating the car, recognize that energy is a force acting through a distance.

so ΔE = F * d

We have ΔE = 3.46E5, and d = 595m, So F = 3.46E5N-m / 595m = 581.5 Newton