Great job on these problems. Most people don't get the second one.
This is the randomized problem set for assignment 2. I chose version 3.
If the velocity of the object changes from 2 cm / sec to 10 cm / sec in 10 seconds, then at what average rate is the velocity changing?
Ave Rate=change in velocity/change in clock time => ave rate= 10cm/s - 2cm/s / 10s = 8cm/s / 10s = 0.8cm/s^2
A ball rolling from rest down a constant incline requires 6 seconds to roll the 61 centimeter length of the incline.
• What is its average velocity?
average velocity='ds/'dt = 61 cm/6s = 10.2cm/s
An object which accelerates uniformly from rest will attain a final velocity which is double its average velocity.
• What therefore is the final velocity of this ball?
the final velocity of the ball would be 10.2cm/s x 2 = 20.4 cm/s
• What average rate is the velocity of the ball therefore changing?
the average rate at which the velocity of the ball is changing is equal to the change in velocity/change in clock time.
=(20.4cm/s - 10.2cm/s) / 6 s = 1.7cm/s^2
An automobile accelerates uniformly down a constant incline, starting from rest. It requires 9 seconds to cover a distance of 124 meters. At what average rate is the velocity of the automobile therefore changing?
Average velocity = 124m/9s = 13.8 m/s
Final velocity = 13.8 m/s x 2 = 27.6 m/s
Average rate = change in velocity/ change in time= (27.6m/s -13.8m/s) / 9s = 1.53 m/s^2