Answer to Question #86148 in Mechanics | Relativity for Khalid Mohammed

Question

ow high should a 3kg mass be lifted from the ground if it is thrown upward at a speed of 25m/s
(Take g=10m/s?

Answer 1

If there is no air friction, apply law of conservation of energy: the kinetic energy will provide the potential energy (i.e. lifting above the ground):

$$KE=PE,$$

$$\frac{1}{2}mv^2=mgh,$$

$$h=\frac{v^2}{2g}=31.25 \text{ m}.$$

The height does not depend on mass.