A boy weighing 350 N runs up a flight of stairs consisting of 20 steps each 10 cm high in 10 seconds. What is power?
power = work/time = 350*20*0.10 J / 10s = ____ W
Power is the rate at which work is done or energy is transferred. It is often measured in watts (W). To calculate power, you need to divide the amount of work done by the time it takes to do that work.
In this case, the work done is the force exerted by the boy multiplied by the distance he moves. The force exerted is equal to his weight, which is 350 N. The distance he moves is the vertical height of the stair, which is 10 cm (0.1 m), multiplied by the number of steps, which is 20. So the total distance is 0.1 m * 20 = 2 m.
The work done is calculated by multiplying the force by the distance: work = force * distance = 350 N * 2 m = 700 J (joules).
Now, since the time taken to do the work is given as 10 seconds, we can use the formula for power:
Power = work / time
Power = 700 J / 10 s = 70 W
Therefore, the power exerted by the boy while running up the flight of stairs is 70 watts.