Question

QUESTION 1

In pole vaulting, a jumper achieves great height by converting their kinetic energy of running in to gravitational potential energy. The pole plays an intermediary role in this process. Suppose that a jumper runs at a speed of 9.1 m s-1, use a simple model to estimate how far the jumper's centre of mass will rise. (For reference only, a new world record was set in early 2014 of 6.16 m.)

QUESTION 2

A hoist system (see figure 3) will be used to raise a load of 675 N at a velocity of exactly 2 m s-1. If the motor efficiency is rated at 90.2% and the gear box efficiency at 85.4% and the winding drum efficiency at 77.4%, calculate the power requirement (in kW) of the motor.

Winding Drum Gear Box Motor 675 N FIGURE 3