Question 1: Define the concept of power in physics and explain its significance in energy transfers.

Answer: Power in physics is the rate at which work is done or energy is transferred over time. It indicates how quickly energy is used or transferred in a process.

Question 2: What is the formula used to calculate power when energy transferred and time are known?

Answer: Power = Energy transferred / Time taken (P = E / t).

Question 3: Calculate the power used when a 500 Joule energy transfer occurs over 25 seconds. Show your working.

Answer: Power = 500 J / 25 s = 20 Watts.

Question 4: A person lifts a box with a force of 200 Newtons to a height of 2 meters in 4 seconds. Assuming all work is transferred as energy, what is the power output? (Use work done = force × distance)

Answer: Work done = 200 N × 2 m = 400 Joules; Power = 400 J / 4 s = 100 Watts.

Question 5: Identify three variables that affect the power output of an engine and briefly explain how they influence it.

Answer: Variables include: (1) Work done or energy transferred—more energy increases power. (2) Time taken—less time increases power. (3) Efficiency—higher efficiency results in more effective power output.

Question 6: In an industrial setting, a conveyor belt moves packages with a power rating of 2.5 kilowatts. If it operates continuously for 8 hours, how much energy does it transfer in that period? Show your calculations.

Answer: Energy = Power × Time = 2,500 W × 8 hours × 3600 s/hour = 2,500 × 28,800 = 72,000,000 Joules or 72 Megajoules.

Question 7: Describe a simple experiment to measure the power output of a toy car powered by a small electric motor. Include the variables you would measure.

Answer: To measure power output, set up the toy car on a flat surface and record the time taken to travel a known distance. Measure the energy supplied to the motor (voltage and current to find electrical energy). Variables include energy supplied, distance traveled, and time taken. Calculate work done (energy transferred) and divide by time to find power.

Question 8: Explain why a more powerful engine is advantageous in transportation vehicles. Include considerations of energy transfer and efficiency.

Answer: A more powerful engine can transfer more energy in less time, allowing vehicles to accelerate faster and carry heavier loads efficiently, reducing travel time and improving performance.

Question 9: Fill in the blank: Power is measured in ________ in the International System of Units.

Answer: Watts

Question 10: A motor transfers 1500 Joules of energy in 30 seconds. What is the power output? Show your work.

Answer: Power = 1500 J / 30 s = 50 Watts.