school
Acemy

Power

AP Physics 1· difficulty 4/5

A car of mass 1500 kg1500\,\text{kg} climbs a 5°5° incline at constant speed 20 m/s20\,\text{m/s}. Rolling and air resistance combined exert a backward force of 400 N400\,\text{N}. Use g=10 m/s2g = 10\,\text{m/s}^2, sin⁡5°≈0.087\sin 5° \approx 0.087. What output power must the engine deliver?

  • A

    approximately 8 kW8\,\text{kW}

  • B

    approximately 34 kW34\,\text{kW}

    check_circle
  • C

    approximately 26 kW26\,\text{kW}

  • D

    approximately 60 kW60\,\text{kW}

Explanation

At constant speed, engine force balances gravity component plus drag: F=mgsin⁡θ+400≈1500⋅10⋅0.087+400≈1700 NF = mg\sin\theta + 400 \approx 1500\cdot 10\cdot 0.087 + 400 \approx 1700\,\text{N}. Power P=Fv≈1700⋅20=34,000 W=34 kWP = Fv \approx 1700\cdot 20 = 34{,}000\,\text{W} = 34\,\text{kW}.

Want 10 more like this — adaptive to your weak spots?

Practice 10 like thisarrow_forwardPredict my AP score

Related questions

auto_awesomeAll Toolsquestion_answerHomework Q&Amenu_bookAP & SAT PreptimelineLearn Mode