Question

Anand gets into an elevator and travels 50 m straight up in a time of 5 s. He then travels in the opposite direction, straight down, for 70 m in a time of 6 s. What is his average speed and velocity, respectively, over the 11 s period?

A. 10.9 m/s, 1.82 m/s
B. 10.9 m/s, −1.82 m/s
C. 21.8 m/s, 10.9 m/s
D. −10.9 m/s, 5.2 m/s

Answer 1

Anand's average speed and velocity over the 11 s period are 10.9 m/s and -1.82 m/s, respectively, calculated by using the total distance of 120 m and a net displacement of -20 m.

Step-by-step explanation:

To calculate Anand's average speed and average velocity over the 11 s period, we should first calculate the total distance traveled and the net displacement. Anand travels 50 m up and then 70 m down, which gives a total distance traveled of 50 m + 70 m = 120 m. The net displacement, however, is the difference between the final and initial position which is 50 m - 70 m = -20 m (downwards).

The average speed is given by the total distance traveled divided by the total time. Thus, the average speed = 120 m / 11 s = 10.9 m/s.

The average velocity, on the other hand, accounts for direction and is defined as the net displacement divided by the total time. Thus, the average velocity = -20 m / 11 s = -1.82 m/s.

Hence, the correct answers are Anand's average speed of 10.9 m/s and average velocity of -1.82 m/s.

Answer 2

10.9 m/s, −1.82 m/s

Step-by-step explanation:

We have,

Anand gets into an elevator and travels 50 m straight up in a time of 5 s. He then travels in the opposite direction, straight down, for 70 m in a time of 6 s.

Total time of journey is 11 seconds.

Total distance is 50 m + 70 m = 120 m

Total displacement is 50 m - 70 m = -20 m

Average speed,
`s=(120\ m)/(11\ s)=10.9\ m/s`

Average velocity,
`v=(-20\ m)/(11\ s)=-1.82 \ m/s`

So, the correct option is (b) 10.9 m/s, −1.82 m/s.