A referee tosses a coin straight up with a velocity of 5.25 m/s, how high does it go above its point of release? (Hint: How fast is it moving at the maximum height?)

Answer 1

The vertical velocity is 0 at the top

v = Vi - 9.81 t

0 = 5.25 - 9.81 t

t = .535 second to the top

h = 0 + Vi t - 4.9 t^2

h = 5.25 (.535) - 4.9 (.535^2)

h = 1.40 meter

alternate and faster way:

(1/2) m v^2 = m g h
[ conservation of energy ]
h = v^2/2g = 5.25^2/19.6 = 1.40 meter