Answer
a) -39 400 m/s
b) -5.78 $\times 10^{-4}$ $m/s^{2}$
Work Step by Step
a)
$\Delta$ v
= v - u
= -18.5 - 20.9
= -39.4 km/s
= -39 400 m/s
b)
time in seconds
= 2.16 years $\times$ 365 days/year $\times$ 24 hours/day $\times$ 60 min/hours $\times$ 60 sec/min
$\approx$ 6.81 $\times$ $10^{7}$ seconds
a
= $\frac{\Delta v}{t}$
= $\frac{-39 4000}{68 100 000}$
$\approx$ -5.78 $\times 10^{-4}$ $m/s^{2}$
