If the mass of the car is 1500 kg, what work must be done to increase the velocity of the car from 30 kmph to 60 kmph?

Correct answer: (b) 156250 J

Explanation

The work needed equals the gain in kinetic energy: W = ½m(v² − u²).

• u = 30 km/h = 25/3 m/s; v = 60 km/h = 50/3 m/s
• v² − u² = (2500 − 625)/9 = 1875/9 m²/s²
• W = ½ × 1500 × 1875/9 = 156,250 J