Moderate -0.3 This is a straightforward application of the power-force-velocity relationship (P = Fv) combined with Newton's second law. Students substitute given values to find driving force, then use F = ma to find net force, and finally subtract to find resistance. It's a standard textbook exercise requiring only direct formula application with no problem-solving insight needed.
2 A car of mass 1200 kg is travelling in a straight line along a horizontal road. At a time when the power of the driving force is 25 kW , the car has a speed of \(12.5 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) and is accelerating at \(1.5 \mathrm {~m} \mathrm {~s} ^ { - 2 }\).
Calculate the magnitude of the resistance to the motion of the car.
2 A car of mass 1200 kg is travelling in a straight line along a horizontal road. At a time when the power of the driving force is 25 kW , the car has a speed of $12.5 \mathrm {~m} \mathrm {~s} ^ { - 1 }$ and is accelerating at $1.5 \mathrm {~m} \mathrm {~s} ^ { - 2 }$.
Calculate the magnitude of the resistance to the motion of the car.
\hfill \mbox{\textit{OCR MEI Further Mechanics Minor Q2 [5]}}