1 A block of mass 15 kg slides down a line of greatest slope of an inclined plane. The top of the plane is at a vertical height of 1.6 m above the level of the bottom of the plane. The speed of the block at the top of the plane is \(2 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) and the speed of the block at the bottom of the plane is \(4 \mathrm {~m} \mathrm {~s} ^ { - 1 }\). Find the work done against the resistance to motion of the block.
……………………………………………………………………………………………......................... .