Calculate the kinetic energy of a body of mass $2 \, kg$ moving with a velocity of $0.1 \, m s^{-1}$. (in $, J$)

Define work. How is work measured? When is work done by a force negative?

$A$ crane pulls up a car weighing $500 \, kg$ to a vertical height of $4 \, m$. Calculate the work done by the crane. (in $J$)

$A$ body of mass $5\, kg$ initially at rest is subjected to a force of $20\, N$. Find the kinetic energy acquired by the body at the end of $10\, s$. (in $, J$)

Avinash can run with a speed of $8 \, m \, s^{-1}$ against a frictional force of $10 \, N$,and Kapil can move with a speed of $3 \, m \, s^{-1}$ against a frictional force of $25 \, N$. Who is more powerful and why?

$(i)$ Define power. Mention its $SI$ unit.
$(ii)$ $A$ boy of mass $50 \, kg$ runs up a staircase of $40$ steps in $8 \, s$. If the height of each step is $15 \, cm$,find his power. (Given,$g = 10 \, m \, s^{-2}$)