Work and energy

Question 1

What is the definition of work of a force (F)?

Answer 1

An object is the product of the force (F) by the distance travelled (d) by the object when the force is in the direction of displacement (cosθ).

Question 2

What is the equation for work and what are the units?

Answer 2

W = force (F) x distance (d) x displacement direction (cosθ)

Units are joules (j)

Question 3

What is potential energy?

Answer 3

Energy that can be accumulated by a system.

Question 4

What is the equation for electrical potential energy?

Answer 4

Ep = k q₁q₂/r

r = distance between point charges q₁ and q₂

Question 5

What is the equation for gravitational potential energy?

Answer 5

Ep = mgh

h is height

Question 6

What is the equation for elastic potential energy?

Answer 6

Ep = (kx²)/2

k is the spring constant
x is displacement

Question 7

What is the equation for kinetic energy and what are the units?

Answer 7

Ek = mv²/2

units of joules (J)

Question 8

What is the equation for power and what are the units?

Answer 8

ΔW/Δt

with a unit of watt (W)

Question 9

What is the equation for mechanical energy (ET) of a system?

Answer 9

ET = Eᴋ + Eᴘ