Physics-Work and Power-Help Please? Thanks!?

Could someone help me with this problem. Please explain what equation I should use and how I go about solving it. I don't know how to do it. It would be greatly appreciated. Thanks!

1.) A 1500kg car accelerates uniformly from rest to 10m/s in 3 secs.

a.) What is the work done on the car in this time period?

b) What is the power delivered by the engine in this time period?

Thanks again! 10 Points Available!!!!

2 Answers

Relevance
  • 1 decade ago
    Favorite Answer

    a. Calculate work. Work is the the amount of energy transferred by a force, done over a net distance.

    F = ma

    W = Fd, d is the distance or in this case since we can but don't want to calculate the distance

    W = 1/2 * mv^2

    Plug in the numbers:

    W = 1/2 * 1500kg (10m/s)(10m/s)

    Work = 75 kJ

    b. Calculate the power. Power is the rate at which work is done, so this will be in units per second.

    P = W / t

    P = 75 kJ / 3s

    P = 25 kW

  • 1 decade ago

    ___________________________________________

    Mass of car = 1500 kg

    Initial velocity = u = 0

    Final velocity = v = 10m/s

    time = t = 3 s

    Work done on a body equals increases its kinetic energy

    Initial kinetic energy =KEi=(1/2)mu^2=zero

    Final kinetic energy =KEf=(1/2)mv^2=0.5*1500*( 10 )^2=75000 J

    Increase in kinetic energy =KEf - KEi =75000 J

    Work done on a body = increase in kinetic energy=75000 J

    a)the work done on the car in 3 second is 75000 J

    __________________________

    Power = work / time =75000 /3 =25000 watt = 25 kW

    b) The power delivered by the engine in 3 second is 25000 W or 26 kW

    ____________________________________________

Still have questions? Get your answers by asking now.