Question 116: Motion in 1D

Question

A ball of mass 0.5 kg is dropped from the height of 10 m. The height, at which the magnitude of velocity becomes equal to the magnitude of acceleration due to gravity, is ________ m. [Use g = 10 m/s2]

Accepted Answer

Let at h height its velocity becomes 10 m/s (as given in question)
$$ \Rightarrow {v^2} - {u^2} = 2( - 10) 	imes ( - h)$$
$$ \Rightarrow {v^2} = 20\,h$$
$$ \Rightarrow 100 = 20\,h$$
$$ \Rightarrow h = 5\,m$$
$$h' = 10 - 5 = 5\,m$$

Motion in 1D

A ball of mass 0.5 kg is dropped from the height of 10 m. The height, at which the magnitude of velocity becomes equal to the magnitude of acceleration due to gravity, is ________ m. [Use g = 10 m/s2]

Choose the correct answer: