posted by Faith on .
What is the magnitude of the average acceleration of a skier who, starting from rest, reaches a speed of 7.1 m/s when going down a slope for 4.0 s?
Average acceleration is given by the expression
(final velocity - initial velocity) / time
Note the use of the word velocity instead of speed, since the direction of the movement is important.
In the case of a skiier going downhill, the direction of the speed does not change, so the average acceleration reduces to:
(7.1-0 m s-1)/4s = ? m s-2