Lectures on Physics has been derived from Benjamin Crowell's Light and Matter series of free introductory textbooks on physics. See the editorial for more information....

An accelerating bus

A VW bus with a mass of 2000 kg accelerates from 0 to 25 m/s (freeway speed) in 34 s. Assuming the acceleration is constant, what is the total force on the bus?

We solve Newton's second law for Ftotal = ma, and substitute Δv/Δt for a, giving

Ftotal = mΔv/Δt
= (2000 kg)(25 m/s - 0 m/s)/(34 s)
= 1.5 kN .

Last Update: 2010-11-11