Answer:
250,000 Joules
Step-by-step explanation:
The work required is the amount of energy added, so the answer is the difference in kinetic energy before and after the acceleration of the car. (The problem doesn't say it's flat where the car is, but well assume it since there is no information about an elevation change that would require us to concern ourselves with potential energy!)
W = E_final - E_initial
= 1/2 m v_final^2 - 1/2 m v_initial^2
= 1/2 m (v_final^2 - v_initial^2)
= 1/2 (1000 kg) ( (30 m/s)^2 - (20 m/s^2) )
= 1/2 (1000 kg) (500 m^2/s^2)
= 250,000 kg m^2/s^2
= 250,000 Joules