Answers

2016-04-24T10:48:03+05:30
U=20m/s
a= -5m/s^2
v=0m/s
t=?
we know,
v=u+at
so,
0=20-5t
hence,
t=4 seconds
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2016-04-24T16:04:47+05:30
For the bus,

Initial Velocity, u = 20 m/s
Final Velocity, v = 0 m/s
Acceleration, a = -5m/s²  (minus sign because of deceleration)
Time, t = (?)

We know that,

a = (v - u)/t
∴t = (v - u)/a
∴t = (0 - 20)/(-5)
∴t = (-20)/(-5)
t = 4s

Thus, the bus will take 4 seconds to stop.
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