Power
Physics ⇒ Mechanics
Power starts at 8 and continues till grade 12.
QuestionsToday has an evolving set of questions to continuously challenge students so that their knowledge grows in Power.
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See sample questions for grade 12
Explain the difference between average power and instantaneous power.
Explain why a sprinter has a higher power output than a marathon runner, even if both do similar amounts of work.
If a force is applied perpendicular to the direction of motion, what is the power delivered by the force?
If the velocity of an object doubles, by what factor does the power required to overcome a constant resistive force change?
A 1500 W heater is used for 10 minutes. How much energy does it consume in kilojoules?
A 60 W light bulb is left on for 2 hours. How much energy does it consume in joules?
A car engine does 5000 J of work in 10 seconds. What is the average power output of the engine?
A crane lifts a 1000 kg load to a height of 10 m in 20 seconds. Calculate the average power output. (g = 9.8 m/s²)
If a constant force F moves an object at constant velocity v in the direction of the force, the power delivered is given by:
(1) F/v
(2) F × v
(3) F + v
(4) F - v
Which of the following best describes the relationship between power, work, and time?
(1) Power = Work × Time
(2) Power = Work / Time
(3) Power = Time / Work
(4) Power = Work + Time
Which of the following is NOT a unit of power?
(1) Watt
(2) Joule/second
(3) Newton-meter/second
(4) Joule
Which of the following is the correct dimensional formula for power?
(1) ML²T⁻³
(2) ML²T⁻²
(3) ML²T⁻¹
(4) ML²T⁻⁴
Fill in the blank: 1 horsepower (hp) is equal to ______ watts.
Instantaneous power is defined as the ______ derivative of work with respect to time.
Power is defined as the rate at which ______ is done.
The average power delivered by a force is equal to the total work done divided by the ______ taken.
True or False: If two machines do the same amount of work, the one that does it in less time has more power.
True or False: Power can be negative if the force and velocity are in opposite directions.
True or False: The power delivered by a force is maximum when the force and velocity are in the same direction.
True or False: The power output of a machine can exceed the input power if the machine is very efficient.
