A car accelerates uniformly in a straight line from rest at the rate of 2.3 m/s^2. what is the speed of the car after it has traveled 55m? how long does it take the car to travel 55m?

Question

Physics

Lawrence Martin

3 October, 15:56

A car accelerates uniformly in a straight line from rest at the rate of 2.3 m/s^2. what is the speed of the car after it has traveled 55m? how long does it take the car to travel 55m?

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Answers (1)

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Milton Gibson · Answer 1

According to the 3rd motion equation

vf^2=vi^2+2ad

since it has moved from rest ... therefore vi=0

vf^2=2*2.3*55=253 m/s

so vf=sqr (253) m/s

...

to get tge time ... according to motion 1st equation vf=vi + at

vi=0

therefore,

vf=at

sqr (253) = 2.3t

t=sqr (253) / 2.3

=6.9 sec.

...

or, to get the time according to motion 2nd equation

d=vit+1/2 at^2

vi=0

d=1/2at^2

55=1/2*2.3t^2

t^2=47.8

t=sqr (47.8)

t=6.9sec.