Question

a ball is dropped into a pond from a height of 42.1m .the splash of sound is heard 3.13seconds after the ball is dropped determine the speed of siund.take g=9.8m/s

Answer 1

Speed of sound = 210.5 m/s.

Step-by-step explanation:

Initial height from ground = 42.1 meter.

We have equation of motion ,
`s= ut+(1)/(2) at^2`, s is the displacement, u is the initial velocity, a is the acceleration and t is the time.

In this the velocity of body in vertical direction = 0 m/s, acceleration = 9.8
`m/s^2`, we need to calculate time when s = 42.1 meter.

Substituting

`42.1=0*t+(1)/(2) *9.8*t^2\\ \\ t = 2.93 seconds`

So it will take 2.93 seconds to reach ground.

Extra time taken to hear sound = 3.13 - 2.93 = 0.2 seconds

Distance travelled by sound = 42.1 m

Speed of sound = Distance / Time = 42.1 / 0.2 = 210.5 m/s.

Speed of sound = 210.5 m/s.