Question

A ball is thrown straight up with an initial velocity of 35 mph. How high does it go (as measured from its initial height)? Answer in meters.

Answer 1

1 mile = 1.60934 km = 1609.34 m

35 mph = 56326.9 m/h

m/h to m/s

56326.9 m/h \(*\dfrac{1~h}{60~min}*\dfrac{1~min}{60~sec}=15.646361~m/s \approx ~15.7~ m/s\)

use: \(\sf v_f^2=v_i^2+2a\Delta y\)

the ball comes to a stop at the top, so \(\sf v_f=0\)

\(\sf (0)^2=(15.7~ m/s)^2+2(-9.8~/s^2)\Delta y\)

\(\Delta y=12.49~m \approx 12.5~m\)