An iron sphere of mass $10 \, kg$ has the same diameter as an aluminium sphere of mass $3.5 \, kg$. Both spheres are dropped simultaneously from a tower. When they are $10 \, m$ above the ground,they have the same

When the speed of a moving object is doubled,its:

List two conditions which need to be satisfied for the work to be done on an object.

Define work,energy,and power. Give the $SI$ units for each of these quantities. $A$ man whose mass is $80 \, kg$ climbs up $30$ steps of the stairs in $30 \, s$. If each step is $12.5 \, cm$ in height,calculate the power used in climbing the stairs. $(g = 10 \, m \, s^{-2})$

$A$ man drops a $10 \, kg$ rock from the top of a $20 \, m$ ladder. What will be its kinetic energy when it reaches the ground? What will be its speed just before it hits the ground? (Take $g = 10 \, m s^{-2}$)

$A$ weightlifter lifts $240 \,kg$ from the ground to a height of $2.5 \,m$ in $3 \,s$. The average power is: