Question

A boy is throwing balls into the air one by one in such a way that when the first ball thrown reaches maximum height he starts to throw the second ball. He repeats this activity. To what height do the balls rise if he throws twice in a second? (Ans: 1/4m)

Answer 1

Consider that the Balls are undergoing free fall

Now ,

Maximum height reached by the ball = ?

Time = 1 seconds ( As he throws twice a second
He throws a ball at 0 second and at 1 second)

We know that,

For a body freely falling under gravity.
v = 0
a = -g
s = H ,
Now use Equation of motion ,
s = vt - 1/2at²
H = 0t - 1/2 ( -g )t²
H = 1/2gt²



H = 1/2 * gt²

Now ,

$H = \frac{1}{2} gt^{2} \\ = 1/2 *10 * (1)\\ = 10/2 \\ = 5 m$

I guess the answer given there is wrong .