Question

Suppose a skydiver (mass = 75kg) is falling toward the earth. When the skydiver is 100m above the earth, he is moving at 60m/s. At this point, calculate the skydiver’s:

• Gravitational Potential Energy
• Kinetic Energy
• Total Mechanical Energy (kinetic + potential)

Answer 1

gravitational potential energy is given as

$PE = mgH$

here given that

m = 75 kg

g = 9.8

H = 100 m

now plug in all value above

$PE = 75 * 9.8* 100$

$PE = 73500 J$

now for kinetic energy we can use

$K = \frac{1}{2}mv^2$

here we have

m = 75 kg

v = 60 m/s

now we have

$K = \frac{1}{2}*75*60^2$

$K = 135000 J$

now for mechanical energy we have

$ME = KE + PE$

so now we will add above to energy to find mechanical energy

$ME = 73500 + 135000$

$ME = 208500 J$