Power lesson 01/27/2021

Power

SWBAT define power and its units.

Multiple Choice

Describe the work done in the picture if the porter moves up some stairs to the other platform

• There will be no work done

• positive work done

• negative work done

Multiple Choice

Describe the work done in the picture if the porter moves forward onto a train with the luggage

• There will be no work done

• positive work done

• negative work done

What is power in physics?

• In science and engineering, Power is the time rate of doing work or delivering energy, expressible as the amount of work done W, or energy transferred, divided by the time interval (Power=W/t)

• The rate of energy transfered.

Power units

• The unit of power is watts.

• 1 watt = 1 joules divided by seconds.

Multiple Choice

What is the equation used for calculating power from force and velocity

• Power = force/velocity

• Power = force * velocity

• Power = force + velocity

• Power = velocity / force

Multiple Choice

Standard unit for Power

• Ampere

• Newton

• Joule

• Watt

Multiple Choice

To solve for power, we use the formula: Power = Work divided by _________.

• Velocity

• Force

• Distance

• Time

Multiple Choice

In physics, power is the rate at which _________ is used.

• Current

• Speed

• Energy

• Force

Multiple Choice

If a person does the same amount of work as someone else in half the time, which of the following is true?

• they did twice the work
• they did half the work
• they have twice the power
• they have half the amount of power

Multiple Choice

It takes work to lift a rock. How much work does it take to lift a rock 3 times higher?

• three times as much
• two times as much
• four times as much
• ten times as much

Multiple Choice

In the formula, what does t represent?

• time

• work

• power

• watt

Multiple Choice

In the formula, what does W represent?

• work

• power

• time

• watt

Multiple Choice

In the formula, what does P represent?

• power

• work

• time

• watt

Multiple Select

Select all: Work is equal to...

• KE + PE

• Change in energy

• mg

• Fd

Multiple Choice

Power is

• the ability to do work.
• the rate at which work is done.
• the force applied to an object for a distance.
• none of the above.

Multiple Choice

What is the SI unit for mass?

• kilogram
• gram
• pound
• newton

Multiple Choice

What is the SI unit for speed?

• meter per second
• meter per second squared
• meter
• second

Multiple Choice

What is the SI unit for time?

• second
• minute
• hour
• meter per second

Multiple Choice

In the formula, what does F represent?

• work

• force

• distance

• watt

Multiple Choice

In the formula, what does W represent?

• work

• force

• distance

• watt

Multiple Choice

Which equation is the one for power?

• P = F/A

• W = F x t

• p = m v

• P = W / t

Multiple Choice

If you pull the trolley along a flat floor horizontally. Which force do you use to calculate the work done.

• Weight

• Pulling force

Multiple Choice

What is the equation for work?

• E_p= mgh

• W = F x d

• F = mg

• F = ma

Multiple Choice

Which requires more power – a person walking up stairs or a person running up stairs?

• walking

• running

• they require equal power output

• no power is required at all

Multiple Choice

Which requires more work – a person walking up stairs or a person running up stairs?

• walking

• running

• they require equal work

• no work is required for either because the movement is vertical

Multiple Choice

What is the unit for power?

• what

• watt

• joule

• Jewel-Osco

Multiple Choice

The unit of work is

• watt

• hertz

• joule

• pascal

Multiple Choice

Which of the following is defined as an energy transfer?

• kinetic energy

• work

• potential energy

• chemical energy