Chapter 5, Work Energy and Power

Question 1

Defining equation for work done?

Answer 1

W = Fx cos(θ) (work = force * displacement in direction of force).

Question 2

Difference between work and energy?

Answer 2

Energy is capacity to do work or work done = energy transferred.

Question 3

What are the different forms of energy?

Answer 3

Kinetic, gravitational PE, chemical, elastic PE, electrical PE, nuclear, electromagnetic, sound (or KE), internal/thermal.

Question 4

Formula for kinetic energy?

Answer 4

(mv^2)/2 (half mass * velocity squared).

Question 5

Formula for change in GPE?

Answer 5

ΔGPE = mgΔh (mass * gravitational field strength * change in height) assuming uniform field.

Question 6

If using energy to find velocity of an object falling down a slope which forms of energy must you take into account?

Answer 6

GPE, KE and energy lost due to resistive forces (Fx).

Question 7

Defining equation for power?

Answer 7

P = W/t (power = rate of change of work done)

Question 8

Unit for Energy?

Answer 8

Joule (J)

Question 9

Unit for power?

Answer 9

Watt (W)

Question 10

Equation for power that isn’t P=W/t?

Answer 10

P=Fx (Power = force * velocity)