Question

a ball thrown straight up takes 2 s to reach a height of 40 m. Find (a) its initial speed (b) its speed at this height (c) how much higher tue ball will go​

Answer 1

Answer:

initial velocity=30m/s

velocity at 40m=10m/s

total height h=45m

Explanation:

Let vf1 is velocity of ball at height h1 =40m and vi is its initial velocity.

g=10m/s2 , t=2sec

Using 1st equation of motion:

vf1-vi = -gt…………………….Retardation

vi=gt+ vf1  

vi=20+ vf1……………………………………………………………………………...(1

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