Question

A student starts from rest from his house and accelerates uniformly at the rate of 2m/sec^2 for 30 sec then he apply break for 45 sec and come to rest at his school.how far is his school

Answer 1

d = 0.5a*t^2
d1 = 1*30^2 = 900 m. = Distance traveled in 30 s.
V = at = 2*30 = 60 m/s = Velocity reached in 30 s.

a=(V-Vo)/t = (0-60) / 45 = -1.33 m/s^2.
V^2 = Vo^2 + 2a*d
0 = 60^2 - 2.66d
2.666d = 3600
d2 = 1350 m.

d1 + d2 = 900 + 1350 = 2250 m. =
Distance from house to school.