kinematics 12th

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A body is thrown vertically upwards with an initial velocity u reaches the maximum height in 6s. The ratio of the distance traveled by the body in first second to seventh second is

 

Initial velocity u = g×t = 9.8×6 = 58.8 m/s
 
distance S1 travelled in first second is calculated using " S = u×t - (1/2)×g×t2 ", using u = 58.8 m/s, and t = 1 s;
 
S1 = 58.8×1 -(1/2)×9.8×1×= 53.9 m
 
Since the paticle reaches maximum height in 6 s, at 7th second travel, its initial velocity is zero.
 
hence distance S7 travelled in 7th second = (1/2)×9.8×1×1 = 4.9 m
 
hence the ratio S1 / S7 = 53.9 / 4.9 = 11

 

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