Question 1158496
a) 
v=u+at

v= 0+2*10

v= 20m/s...........................(1)

s=ut+1/2 * a*t^2

=1/2* 2*100

= 100 m

b) 300 m  for 20 s
v= 15m/s

deceleration distance = distance = 0.5 x deceleration x time^2 = 0.5 x 2.0 m/s^2 x (5 s)^2 = 25 m

Average velocity = (100+300+25 )=425/35     ( 35 s total time taken)

= 12.14 m/s