Question

An elevator travels 28m upwards to the 8th floor in 9.5 seconds, wait for 20 seconds as somebody gets on then travels down 10m down to the 5th floor at a speed of 3.0m/s? What is the average speed of the elevator during this time. What is the average velocity of the elevator?

Answer 1

The average speed of the elevator is approximately 1.16 m/s, and the average velocity is approximately 0.55 m/s, considering the total distance traveled and the total time taken, including stops and speed changes.

Step-by-step explanation:

To calculate the average speed of the elevator, we must consider the total distance traveled divided by the total time taken. The elevator travels 28m upwards, waits for 20 seconds, and then travels 10m downwards. To find the average velocity, we should consider the total displacement (which is the net change in position) divided by the total time. The displacement is 28m - 10m = 18m (upwards). The speed of the elevator when going down is given as 3.0 m/s, so we use this to find the time taken to travel 10m down: time = distance/speed = 10m/3.0m/s = 3.33s. The total time for the trip is 9.5s + 20s + 3.33s = 32.83s.

The average speed = total distance / total time = (28m + 10m) / 32.83s = 38m / 32.83s ≈ 1.16 m/s. The average velocity = total displacement / total time = 18m / 32.83s ≈ 0.55 m/s.