Question

10. A car starts from the rest and attain velocity of 8m/s in 80s. Then he applies brakes such that the velocity of the car comes down to 2mls in the next 5s. calculate the acceleration the car in both the cases. ?
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Answer 1

Answer:

Explanation:=

​The initial velocity of car at time t = 0 sec. = at rest

The velocity after time t =1 sec. = 20 m/sec.

The velocity after time t = 2 sec = 40 m/sec.

The velocity after time t = 3 sec = 60 m/sec

Using the relation

v = u + a t,

where u = initial velocity in m/sec,

a= acceleration in m/sec^2

t = time in seconds in which the initial velocity changes from u m/sec to v m/ sec.

we get acceleration a = 20 m/sec^2, in every of time interval of 1 sec. i.e in the interval 0 sec to 1 sec, in the interval 1 sec to 2 sec, in the interval 2 sec. to 3 second. This means that the car is moving with a uniform acceleration, provided the direction of car does not change also