Question

19 multiple choice 3 points
power is work done over a distance
false
true
20 multiple choice 5 points
a slanted surface used to raise an object is a(n)
effort ramp
screw
efficiency board
inclined plane

Explanation:

Question 19

Power is defined as the rate of doing work, i.e., \( P=\frac{W}{t} \), where \( W \) is work and \( t \) is time. Work is done when a force causes displacement (\( W = F\times d \), where \( F \) is force and \( d \) is displacement in the direction of force). So power is related to work done over time, meaning power does involve work done (over a duration). Thus the statement "Power is work done over a distance" is incorrect because power is work done over time, not distance.

• An inclined plane is a simple machine with a slanted surface (ramp - like) that allows raising an object with less force by increasing the distance over which the force is applied.
• "Effort ramp" is not a standard term for this simple machine.
• A screw is a different simple machine (an inclined plane wrapped around a cylinder).
• "Efficiency board" is not a recognized term for a simple machine used to raise objects.

So the correct term for a slanted surface used to raise an object is an inclined plane.

Answer:

False

Question 20