Answer:
V=28.5m/s
b=V=28.5m/s
c=V=28.5m/s
Explanation:
A slingshot fires a pebble from the top of a building at a speed of 15.0 m/s. The building is 30.0 m tall. Ignoring air resistance, find the speed with which the pebble strikes the ground when the pebble is fired.
(a) horizontally,
(b) vertically straight up,
(c) vertically straight down.
u=15m/s
yi=30m
v=?
yf=0
system=pebble+earth
workdone=0
chnage in energy=0
ki+Ui=Kf+Ui
K=kinetic energy
U=potential energy
1/2mv^2+mgyf=1/2mu^2+mgyi
V^2=u^2+2gyi
V=[tex]\sqrt{15^2+2*9.81*30}[/tex]
V=28.5m/s
b. and c will be the same as a. because the magnitude of the kinetic energy is dependent on the velocity and not the magnitude which the pebble is tilted at
