Mechanics (Work, Energy, Power)

Question 1

What is the principle of the Conservation of Energy

Answer 1

In a closed system, total energy will always be conserved

Question 2

Define “Work”

Answer 2

The Scalar dot product between force and displacement
(when a force causes a displacement)
* Scalar dot product = Force MUST be parallel to the displacement (or you only measure that component)
* Measured in Joules (J) = Nm (Newton x Meter)
* Scalar quantity

*Also describes the change in energy (final - initial) (work needed to to raise a book from a table to a high shelf is difference of GPE when book is on shelf to when book was at table)

Question 3

How do you find Work in a graph? (What kind of graph?)

Answer 3

In a force-distance graph, the area under the curve is the Work done

Question 4

What is Hooke’s Law?

Answer 4

the force needed to extend or compress a spring by some distance is proportional to that distance
F=kx

k= spring constant

Question 5

Define “Power”

Answer 5

Rate at which work is done (work/”energy change” over time)

* Measured in Watts (W) = Js(-1) (Joules per second)