Physics Homework

posted by .

I have a few questions that I don't understand and would like to get checked, please?

5.If energy is conserved and momentum is conserved, would they both have to be conserved simultaneously in some interaction?

My answer: No because each engergy and momemtum is being conserverd.

9. A 60 kg skydiver moving at terminal speed falls 50m in 1 s. What power is the skydiver expending on the air?

My answer: p=work/time
p=50m/1s=50 Watt

12.Where, exactly, does the energy stored in oil come from? How can we get "work" from oil? In your discussion, try to use the words work, energy, heat, power, and conservation in their correct physical sense.

-I don't understand this question.

  • Physics Homework -

    The answer to 5. is yes, but some of the energy may be heat and not show up in equations of motion. Only elastic collision conserve (kinetic + potential) energy.

    9. Your equation is wrong. You cannot divide distance by time to get power. At terminal speed,
    (powerloss) = weight x velocity.
    The average power for the one second is M g/(1 sec)

    12. The energy from oil starts with chemical energy in the molecules that gets converted to heat in an engine (by reacting with oxygen), and then converted to mechanical energy when a piston is pushed by hot combustion products.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. physics

    Is it true or false that momentum is conserved when total mechanical energy is conserved?
  2. physics

    Is it true or false that momentum is conserved when total mechanical energy is conserved?
  3. physics

    Momentum is conserved whenever total mechanical energy is conserved. I believe this is false. Am I correct?
  4. physics

    Which of the following statements is true for an inelastic collision?
  5. Physics

    Which of the following statements is true for an elastic collision?
  6. Physics

    You drop an egg from rest with no air resistance. As it falls, a. only its momentum is conserved. b. only its kinetic energy is conserved. c. both its momentum and its mechanical energy are conserved. d. its mechanical energy is conserved, …
  7. physics

    Determine for each of the following statements whether it is always true or can be false. In a perfectly inelastic collision, the kinetic energy is conserved. Kinetic energy is conserved in an elastic collision. Two objects of different …
  8. Physics

    Consider an isolated system consisting of two masses, each of which has a velocity vector in two dimensions. When these two masses collide the total momentum of the system is conserved. (a) Show that if the total momentum of the system …
  9. Physics

    Does the total kinetic energy of an isolated system necessarily have to be conserved when its total momentum is conserved?
  10. AP Physics - collisions?

    Two steel balls collide and bounce apart in an isolated system. If the final kinetic energy is less than the initial kinetic energy, what of the following is true?

More Similar Questions