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
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)
A cyclist applies a force of 100 N to move at a constant speed of 5 m/s. What is the power output?
A machine does 2000 J of work in 5 seconds. If the efficiency of the machine is 80%, what is the useful power output?
A motor lifts a 500 N weight at a constant speed of 2 m/s. What is the power developed by the motor?
A person lifts a 20 kg box to a height of 2 m in 4 seconds. Calculate the power expended. (Take g = 9.8 m/s²)
A pump raises 600 liters of water per minute to a height of 10 m. Calculate the power required. (Density of water = 1000 kg/m³, g = 9.8 m/s²)
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?
State the formula for instantaneous power in terms of force and velocity vectors.
The power required to lift a 50 kg mass vertically upward at a constant speed of 0.5 m/s is: (Take g = 9.8 m/s²)
