Question

Please help with this and explain it,if you can.

Answer 1

Answer:

displacement at 45 s  =  30

                           65 s  = 50

So the average speed over the interval from 45 s to 65 s is

(50 - 30) cm / 20 s = 1 cm / sec

As a check an average speed of 1 cm / sec for 20 sec will produce a

displacement of 1 cm / sec * 20 sec = 20 cm  or from 30 to 50 cm