## anonymous 5 years ago 23. A student uses a compressed spring of force constant 22 N/m to shoot a 7.5 x 10 power of -3 kg eraser across a desk. The magnitude of the force of friction on the eraser is 4.2 x 10 power of -2 N. How far along the horizontal desk will the eraser slide if the spring is initially compressed 3.5 cm? Use the law of conservation of energy.

We can calculate the potential energy stored in spring by equation $1/2 k x^{2}$ where k is force constant and x is the compression. You will get 134.75 J energy. If the whole amount of energy is transfered to eraser then we can use energy conservation as the work done in traveling the distance y on a horizontal desk = Initial energy of eraser If we take constant friction force acting on an eraser then $work done = force \times displacement$ and this equal to energy of eraser 135.75 J by solving this we get the distance travel by eraser is 3232.14 meter