$A$ ball is allowed to fall from a height of $10 \, m$. If there is $40 \%$ loss of energy due to impact,then after one impact the ball will rise to a height of ........ $m$.

$A$ particle of mass $m$ starts moving from the origin along the $x$-axis and its velocity varies with position $x$ as $v = k \sqrt{x}$. The work done by the force acting on it during the first $t$ seconds is ...........

$A$ block of mass $5 \ kg$ is lifted to a height of $5 \ m$ by a force of $60 \ N$. Find:
$(1)$ Work done by the force.
$(2)$ Potential energy of the block at $5 \ m$.
$(3)$ Kinetic energy of the block at $5 \ m$.
$(4)$ Velocity of the block at $5 \ m$. (Take $g = 9.8 \ m/s^2$)

$A$ man throws a ball with a speed of $12 \ m/s$ at a height of $12 \ m$. If he throws the ball such that it just reaches this height,what is the percentage of energy saved?

$A$ ball of mass $0.2 \,kg$ is thrown vertically down from a height of $10 \,m$. It collides with the floor and loses $50 \%$ of its energy and then rises back to the same height. The value of its initial velocity is

$A$ box of mass $3 \,kg$ moves on a horizontal frictionless table and collides with another box of mass $3 \,kg$ initially at rest on the edge of the table at height $1 \,m$. The speed of the moving box just before the collision is $4 \,m/s$. The two boxes stick together and fall from the table. The kinetic energy just before the boxes strike the floor is (Assume, acceleration due to gravity, $g=10 \,m/s^2$) (in $\,J$)