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

Answer:

10.9 m/s, −1.82 m/s

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, $s=\dfrac{120\ m}{11\ s}=10.9\ m/s$

Average velocity, $v=\dfrac{-20\ m}{11\ s}=-1.82 \ m/s$

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