Question

With what minimum speed must you toss a 200 g ball straight up to just touch the 12-m-high roof of the gymnasium if you release the ball 1.4 m above the ground? Solve this problem using energy. Express your answer to two significant figures and include the appropriate units.

Answer 1

Answer:

v = 14.41 m/s

Explanation:

It is given that,

mass of the ball, m = 200 g = 0.2 kg

Height of the roof, h = 12 m

The ball is tossed 1.4 m above the ground, h' = 1.4 m

Let v is the minimum speed with which the ball is tossed. Using the conservation of energy to find it as :

$E_p=E_k$

$mg(h-h')=\dfrac{1}{2}mv^2$

$g(h-h')=\dfrac{1}{2}v^2$

$v=\sqrt{2g(h-h')}$

$v=\sqrt{2\times 9.8(12-1.4)}$

v = 14.41 m/s

So, the minimum speed with which the ball is thrown straight up is 14.41 m/s. Hence, this is the required solution.