Answer:
a) 0.05719 km/s^2
b) 0.00921 km/s^2
Explanation:
average acceleration can be calcuated as follows
[tex]a=\frac{\Delta v}{\Delta t} = \frac{v_f-v_i}{t_f-t_i}[/tex]
a)
- In the initial time ([tex]t_i=0[/tex]), just before of race start the rocket is at rest. So [tex]v_i=0[/tex].
- After 3.22 s the rocket reach 663 km/h, So [tex]t_f=3.22 s[/tex] and the [tex]v_f=663 km/h[/tex]. We convert units from km/h to km/s to have the same time units (seconds) the velocity would be:
[tex]663 \frac{km}{h}*\frac{1 h}{3600 s} = 0.18467 km/s[/tex]
(take into accoun that 1 h=3600 s)
and acceleration is:
[tex]a= \frac{0.184167 km/s-0 km/s}{3.22s-0s}= 0.05719 km/s^2[/tex]
b)
acceleration while stopping is calculate with the same formula but now
-we define the initial time ([tex]t_i=0[/tex]) the instant just before begining the stopping. At this instant the velocity is 663 km/h which is the same as 0.18467 km/s.
-After 20 seconds the rocket stops. So tex]t_f=20 s[/tex] and [tex]v_f=0[/tex]
So, acceleration is:
[tex]a= \frac{0km/s-0.184167 km/s}{20s-0s}= 0.00921 km/s^2[/tex]
