Work & Velocity: Solve 100m Distance, 2 Ton Car

[herbgriffin]

Homework Statement

The driver of a car wishing to save the fuel takes his leg off the accelerator when the car is moving at a maximum speed of 80 kmph. Determine the speed of the car after traveling a distance of 100m. The mass of car is 2 tons and the force of friction is 0.6 kN/ ton.

Homework Equations

Work = Force * distance
kinetic force = 1/2 (mV^2 - mVi^2)

The Attempt at a Solution

Frictional force = 0.6kN/ton( 2 tons) = 1.2 kN
Vi= 80 kmph = 22. 22 m/s
i don't know how to start please help me ...please..

 

[ashishsinghal]

use equation of motion
v^2 = u^2 + 2as

 

[HallsofIvy]

Why are you trying to calculate work? The problem does not ask for that. You have the friction force so can calculate the deceleration (negative acceleration). Use the formula that ashishsinghal gives.