a body is projected horizontally with speed 5m/s from height h,takes 8sec to reach the ground .the time it takes to cover the first onefourth of height is?
Answers
Answered by
65
h=1/2 gT^2= 320 m
h/4= 80 m
1/2 gt^2= 80
t= 4 sec
Answered by
35
Given: Speed = 5m/s
Height = h
Time = 8 seconds
To find: Time is taken to cover the first one-fourth of the height
Solution:
Distance traveled by the body when it was thrown with a velocity of 5 m/s
The final velocity will be zero because the body is projected horizontally.
From the law of kinetics,
S = ut + 1/2gt²
= 5×8 + 1/2×10×(8)²
= 40 + 320
= 360 m
According to the question we have to find the time taken by the body to reach one-fourth of height,
One-fourth of height = 360/4 = 80m
Therefore, from the law of kinetics,
S = 1/2gt²
80 = 1/2×10t²
16 = t²
t = 4 seconds
Therefore, the time it takes to cover the first one-fourth of height is 4 seconds.
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