Question

a baseball is thrown vertically upwards and returns to the thrower three seconds later find speed at which the ball us thrown​

Answer 1

14.7 m/s

Step-by-step explanation:

Since the motion of the ball is a uniformly accelerated motion, we can find the initial speed by using the following suvat equation:

`s=ut+(1)/(2)at^2`

where

s is the vertical displacement

u is the initial velocity

t is the time

a is the acceleration

In this problem, we have:

s = 0 (because at the end of the motion, the ball returns to its original position)

u = ?

`a=g=-9.8 m/s^2` is the acceleration of gravity (negative because it is downward)

`t = 3 s` is the total time of flight

Solving for u, we find the initial velocity of the ball:

`0=ut+(1)/(2)at^2\\u=-(1)/(2)at=-(1)/(2)(-9.8)(3)=14.7 m/s`