Power, Efficiency, and Work Concepts

The video tutorial covers the concepts of power and efficiency, explaining power as the rate of work done or energy transferred, measured in watts. It uses examples like lifting an apple and a monkey doing push-ups to illustrate power calculations. The tutorial also discusses kilowatt hours as a unit of energy and explains efficiency using Sankey diagrams. It concludes with examples of inclined planes and pulleys, highlighting their mechanical advantages and efficiency.

What is the unit of power named after James Watt?

• Newton

• Joule

• Watt

• Pascal

If an apple is lifted with a force of 1 Newton through 1 meter, how much energy is used?

• 1 Joule

• 100 Joules

• 0.1 Joules

• 10 Joules

How many times would you need to lift an apple per second to match the power of a 100-watt light bulb?

• 10 times

• 200 times

• 50 times

• 100 times

What is the power output of a monkey doing push-ups if it lifts its center of mass by 0.3 meters in 2.4 seconds?

• 200 watts

• 20 watts

• 50 watts

• 100 watts

What is the relationship between power, force, and speed for an object moving at constant velocity?

• Power = Force / Speed

• Power = Force x Speed

• Power = Force + Speed

• Power = Speed / Force

In a 100% efficient machine, how does the input work compare to the output work?

• Output work is greater

• Cannot be determined

• Input work is greater

• They are equal

What percentage of input power is typically converted to light in an incandescent bulb?

• 5%

• 25%

• 50%

• 95%

How is efficiency calculated in terms of power?

• Input power / Output power

• Output work / Input work

• Output power / Input power

• Input work / Output work

What is the efficiency of a frictionless inclined plane?

• 100%

• 0%

• 50%

• 75%

In a pulley system, what is the trade-off when using less force to lift an object?

• More time required

• Less distance to pull

• Less time required

• More distance to pull