Posted by RE on .
It takes 180 kJ of work to accelerate a car from 21.0 m/s to 27.5 m/s. What is the car's mass?
kg?

Physics 
MathMate,
Initial kinetic energy
= (1/2)mv0²
Final kinetic energy
= (1/2)mv1²
Difference
E = (1/2)m(v1²v0²)
Solve for m