Practicing Success
Consider a drop of rain water having mass 1 g falling from a height of 1 km. It hits the ground with a speed of 50 m/s. Take g constant with a value 10 m/s2. The work done by the (i) gravitational force and the (ii) resistive force of air is : |
i) 10 J ii) -8.75 J i) - 10 J ii) - 8.75 J i) 1.25 J ii) -8.75 J i) 100 J ii) 8.75 J |
i) 10 J ii) -8.75 J |
According to work energy theorem wg + wR = \(\frac{1}{2}mv^2\) wg = mgh =10-3 x 10 x 103 = 10J 10 + wR =\(\frac{1}{2}\) x 10-3 x 50 x 50 10 + wR = 1.25 wR = -8.75J |