Question

A stone is released from the top of a tower such that it covers 25 m during the third second. The average speed
of the stone during three seconds is:

Answer 1

Answer:

15m/s

Explanation:

Average speed is distance covered divided by the time.

Since, the stone is released from the top of the tower ,the only force acting on it is gravity hence it is a free fall.

Using the equation of kinematics

y=[ut]-[1/2g(t^2)]

y=[0*3]-[1/2*10*9]

y=45m

negative sign is dropped because it is just an indication that the distance is measured from Height y to ground and not from ground to height y.

Average speed distance travelled divided by time.

Average speed =45/3=15m/s!!!!

please note that since the statement is given as dropped I have directly made calculations using u is equal to zero.

The statement regarding the distance travelled in 3rd second is to get information about initial velocity which will turn out to be zero.

Use the formula Snth=(u-[g/2]{2n-1})

You will get u to be zero.

Hope it helps you!!!!