Question

2. In order to crack the sidewalk, a penny must be traveling at a rate of 500 m/s. From how high must you drop an object to reach that rate? How long will it be dropping for before it strikes the sidewalk?

Answer 1

speed = 500 m/s

height = ?

time= ?

This is a problem of free fall

h = vot + 1/2gt^2

vf = vo + gt

t = (vf - vo)/g

t = (500 - 0) / 9.81

t = 500 / 9.81

t = 51 seconds

h = 1/2(9.81)(51)^2

h = 12758 m