$A$ balloon starts rising from the ground from rest with an upward acceleration of $2 \, m/s^2$. Just after $1 \, s$,a stone is dropped from it. The time taken by the stone to strike the ground is nearly ....... $s$.

$A$ man is standing on top of a building $100\, m$ high. He throws two balls vertically,one at $t = 0$ and the other after a time interval $\Delta t$ (less than $2\, s$). The second ball is thrown at a velocity half that of the first. The vertical gap between the first and second ball is $15\, m$ at $t = 2\, s$. The gap is found to remain constant. Calculate the velocity with which the balls were thrown and the exact time interval between their throws.

$A$ body is thrown vertically upwards and takes $5 \text{ s}$ to reach maximum height. The distance travelled by the body will be same in

Discuss the observation of Galileo for the objects falling freely.

What is the initial velocity of an object falling freely (in $m/s$)?

$A$ body is thrown vertically upwards. At half of the maximum height,its velocity is $10 \ m/s$. What is the maximum height attained by the body? (Take $g = 10 \ m/s^2$)