A car is moving at 90km/h can come to a stop in 5 s by slamming on the breaks . Assuming that the velocity is decreasing uniformly during 5s how much distance is needed to make it to stop?
Please help me quick
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Answer:
37.5 m
Explanation:
t = 5s
initial velocity=90km/hr
=90×5/18m/s
=25m/s
final velocity=0 (it stops)
by first equation of motion
v=u+at
0=25+a5
-25/5=a
a = -5ms^-2
by second equation of motion
s=ut+1/2at^2
=25+1/2(-5)(25)
=25+1/2(-125)
=25-62.5
=37.5m
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