Question

A powerful missile reaches a speed of 5 kilometers per second in 10 seconds after its launch. What is the average acceleration of the missile during this period?

a) 0.2 meters/second^2
b) 0.4 centimeters/second^2
c) 0.5 meters/second^2
d) 0.5 kilometers/second^2

Answer 1

Average acceleration is the change in velocity divided by an elapsed time. So, we can calculate it as follows:

acceleration = 5 - 0 / 10 - 0 = 0.5 kilometers/second^2

Therefore the correct answer is option D.

Hope this answers the question. Have a nice day.

Answer 2

Average acceleration = (change in speed) / (time for the change)

The missile's change in speed is (5,000 - 0) = 5,000 m/s

Average acceleration = (5,000 m/s) / (10 sec)

= 500 m/s² (about 51 Gs)

Inconveniently, this isn't one of the choices on the list. Is there something wrong, either with the choices or with my solution ?

No. Relax. Everything is OK.

500 meters is the same thing as 0.5 kilometer. So my answer can also be written as 0.5 km/s² . That doesn't change anything, and it IS one of the listed choices.

The average acceleration is 0.5 km/sec² (d) .