Please help me!

Question

In the high jump, the kinetic energy of an athlete is transformed into gravitational potential energy without the aid of a pole. With what minimum speed must the athlete leave the ground in order to lift his center of mass 1.80 m and cross the bar with a speed of 0.80 m/s?

Answer 1

For this question there are two components needed to figure out the minimum speed, a vertical component and horizontal component.

For the vertical component, you can figure out the speed by setting the initial vertical kinetic energy (KE = 1/2*m*v^2) to the vertical potential energy (PE = m*g*h) for a height of 1.8 m (h = 1.8) to solve for v.

For the horizontal component, the speed needs to be 0.80 m/s and that shouldn't change without air resistance.

So once you have the vertical and horizontal components of speed, you just need to find the resultant speed. Pythagoras can help you with that, a^2 + b^c = c^2.