oh my, still in feet?
in this case g = about 32 ft/s^2
v = 58 - 32 t
at top t = 0
t at top = 58/32 seconds
total time in air by the way = 2 t = 58/16 seconds
now the problem:
h = Vi t - .5 * 32 t^2
H = 58 (58/32) - .5 * 58^2/32
(A.) H = 58^2/64 ft
(B.) 2 t = 58/16 sec
when h = H/2 = 58^2/128
easy way to do this is with energy
Ke at bottom = (1/2) m(58^2)
energy halfway up
= m g h + .5 m v^2
= 32 m H/2 + .5 m v^2
so
(1/2)(58^2) = 16(58^2/64)+ .5 v^2
solve for v
A stone is thrown vertically upward with a velocity of 58 ft./sec.
A.) How high will it rise?
B.) How soon will it reach the ground again?
C.) What is its velocity half-way up?
1 answer
1 answer