Question

A student weighing 550 N takes 15 seconds to run up two flights of stairs to a landing, a total of 5 meters vertically above her starting point. How much power does the student need to do this?

1) 41,250 W
2) 180 W
3) 37 W
4) 96 W

Answer 1

The power needed by the student to run up two flights of stairs in 15 seconds is calculated using the formula for power (P = Work/Time) resulting in an answer of approximately 180 W.

Step-by-step explanation:

The subject of this question is Physics, specifically related to the concept of power. Power is the rate at which work is done or energy is transferred. In this case, we are looking at the power needed by the student to ascend a flight of stairs. The formula used to calculate power (P) is P = Work done (W) / Time taken (t). The work done by the student in running up the stairs against gravity is equal to the gravitational potential energy gained, which is Work (W) = Force (which is weight for vertical displacement) × vertical distance (h). Here, the student's weight is given as 550 N, and the vertical height is 5 meters. The time taken is 15 seconds.

To calculate the power needed by the student to run up the stairs, we can use the formula: Power = Work / Time. The work done by the student is equal to the product of the force applied (weight) and the distance traveled (vertical height).

Calculating the work done: W = 550 N × 5 m = 2750 J (Joules).

Next, we calculate the power: P = 2750 J / 15 s = 183.33 W.

Thus, the correct answer is 2) 180 W, which is the average power needed by the student to climb the stairs in 15 seconds.