In: Physics
A model rocket is shot straight up and explodes at the top of its trajectory into three pieces as viewed from above and shown in the figure below. The masses of the three pieces are
mA = 125.0 g,
mB = 20.0 g,
and
mC = 30.0 g.
Immediately after the explosion, piece A is traveling at 1.40 m/s, and piece B is traveling at 6.90 m/s in a direction 30° below the negative x axis as shown. What is the velocity of piece C?
magnitude | ____m/s |
direction | _____° below the positive x axis |
fiven
ma = 0.125 kg
mb = 0.02 kg
mc = 0.03 kg
take xaxis as i
y axis as j
z axis as k
from conservation of monentum
total initial momentum = total final momentum
o = mava+mbvb+mcvc
0 = 0.125*1.4(j)+0.02*(6.9cos30(-i)+6.9sin30(-j)+0.03*vc
0 = 0.175 j-0.119i-0.069j+0.03vc
0.03vc = 0.119i-0.106j
vc = 3.97 i-3.53 j
this is the velocity of piece c
magnitude = vc = sqrt(3.97^2+(-3.53)^2) = 5.31 m/s
direction = theta = tan^-1(-3.53/3.97) = 41.64 degrees below the positive x axis