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Class 9Class 10First YearSecond Year
$A diver weighing 750 \mathrm{~N} dives from a board 10 \mathrm{~m} above the surface of a pool of water. Use the conservation of mechanical energy to find his speed at a point 5.0 \mathrm{~m} above the water surface neglecting air friction.$

$v. The kinetic energy of a body of mass 2 \mathrm{~kg} is 25 \mathrm{~J} . Its speed is(a) 5 \mathrm{~ms}^{-1} (b) 12.5 \mathrm{~ms}^{-1} (c) 25 \mathrm{~ms}^{-1} (d) 50 \mathrm{~ms}^{-1}$

$6.1 A man has pulled a cart through 35 \mathrm{~m} applying a force of 300 \mathrm{~N} . Find the work done by the man.(10500 J)$

$How large a force is required to accelerate an electron \left(\mathrm{m}=9.1 \times 10^{-31} \mathrm{~kg}\right) from rest to a speed of 2.0 \times 10^{7} \mathrm{~ms}^{-1} through a distance of 5.0 \mathrm{~cm} ?$

$6.5 Define energy give two types of mechanical energy.$

$When a rocket re-enters the atmosphere its nose cone becomes very hot. Where does this heat energy come from?$

$What sort of energy is in the following:(b) Water in a high dam$