An object moving with a speed of 5 m/s comes to rest in 10 s, after
the brakes are applied. What is the initial velocity?
Answers
V^2= U^2 - 2aS
V = Final velocity. Which in this case, 0.
U= Initial Velocity.ie, 10 m/s.
a= acceleration. Here, -2 m/s^2.
S= the required distance to stop.
The equation becomes,
0= U^2- 2aS.
U^2= 2aS.
S= U^2/ 2a.
= 10^2/ 2×2.
100/4
= 25 mts.
Question :
An object moving with a speed of 5 m/s comes to rest in 10 s, after the brakes are applied. What is the retardation rate?
Answer :
The retardation of the body is 0.5 m/s^2.
Given :
Initial velocity of the body = 5m/s
Time taken by it to come to rest = 10s
To find :
The retardation of the body
Solution :
We know that,
v = u + at
where v is the final velocity , u is the initial velocity and a is the acceleration ( here, retardation ) and t is the time taken
Since the object comes to rest ,
v = 0 m/s
According to the problem,
0 = 5 + a (10)
=> 0 = 5 + 10a
=> 10 a = -5
=> a = -5/10
=> a = -1/2 = -0.5 ( the minus sign denotes negative acceleration)
Hence, the retardation of the body is 0.5 m/s^2.
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