Motion in a Straight Line
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Question : 6
Total: 27
A car moving along a straight highway with speed of 126 km h– 1
Solution:
Here, u = 126 k m h − 1
=
m s − 1
= 35 m s − 1
v = 0 , S = 200 m , a = ? t = ?
We know,v 2 = u 2 + 2 a S
∴ 0 = ( 35 ) 2 + 2 × a × 200
ora =
=
= − 3.06 m s − 2
As,v = u + a t
∴ 0 = 35 + (
) t
ort =
=
= 11.43 s
–ve sign shows that acceleration is negative, which is called retardationi.e. car is uniformally retarded ata = 3.06 m s – 2 .
We know,
or
As,
or
–ve sign shows that acceleration is negative, which is called retardationi.e. car is uniformally retarded at
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