How do I solve this?

Question

The Red Bull Cliff Diving World Series this year will take place at Boston Harbor starting June 3rd. Ellie Smart, from Missouri, will be competing. She is one of eight permanent women cliff divers in the Red Bull competition. The women’s diving platform is 70 ft above the water. Assuming Ellie’s initial velocity is negligible and her mass is 56 kg, calculate her velocity (in mph) at 60 ft, 30 ft, and when she hits the water. (Note: gL = 9.8 m/s2 = 32.2 ft/s2)

Answer 1

Assuming you can disregard air resistance, you can use the kinematic equation

vf^2 = vi^2 + 2*g*d

vf = final velocity

vi = initial velocity

g = gravitational acceleration

d = distance

The problem tells us we can assume vi = 0 ft/sec, therefore we can set up our equation as follows

vf = sqrt(2*g*d)

vf = sqrt(2*32.2*d).

After solving at the different heights you will need to change from ft/sec to miles/hr.

(ft/sec)*(1 mile/5280 feet)*(1 min/60 sec)*(1 hr/60 min) = miles/hr