A cricket ball is dropped from a height of 20 m. Calculate : (I) speed of ball when it hits the ground (2)time it takes to fall through this height (g=10m/s2)

Asked by nisha_vini29 | 3rd Nov, 2018, 01:04: PM

Expert Answer:

When the ball is dropped from height h, speed v of the ball when it reaches ground is calculated using the equation, " v2 = 2×g×h "
 
hence speed v = begin mathsize 12px style square root of 2 g h end root space equals space square root of 2 cross times 9.8 cross times 20 end root space almost equal to space 19.8 space m divided by s end style
Time taken t to reach the ground is obtained using the equation " h = (1/2)×g×t2 "
 
hence time taken t to reach ground  = begin mathsize 12px style square root of fraction numerator 2 h over denominator g end fraction end root space equals space square root of fraction numerator 2 cross times 20 over denominator 9.8 end fraction end root equals 2.02 space s end style

Answered by Thiyagarajan K | 4th Nov, 2018, 02:25: AM

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