(a) The time when the speedometer reads 20 m/s is 1 second.
(b) The time when the speedometer reads 0 m/s is 0 s.
How to calculate the time of motion of the ball?
The time of motion of the ball at the different speed shown is calculated by applying the following formula as shown below;
The acceleration of the ball after 2 seconds is;
a = v/t
where;
- v is the reading of the speedometer after 2 seconds = 40 m/s
- t is the time = 2 s
a = 40 m/s / 2 s
a = 20 m/s²
(a) The time when the speedometer reads 20 m/s is calculated as;
t = (v - u ) / a
t = (40 m/s - 20 m/s ) /20 m/s²
t = 1 second
(b) The time when the speedometer reads 0 m/s is calculated as;
t = (v - u ) / a
t = ( 0 m/s ) / 20 m/s²
t = 0 s