Question

a body (A) is moving with a speed of 250m/s in the positive x-direction, collides with body (B) initially at rest and having the same mass as (A). after collision the speed of body (A) is 100m/s making 30 degree with the horizontal. the speed and direction of body (B) after the collision is:

a) 50 m/s f= 71 degree
b)25 m/s f= 30 degree
c) 171 m/s f= 17 degree
d) 342 m/s f= 34 degree

Answer 1

assume each mass is 1 kilogram
momentum before = momentum after
i is x direction, j is y direction
before = 250 i and 0 j
after
Ai = 100 cos 30
Aj = 100 sin 30 = 50
Since Aj + Bj = 0,
Bj = -100 sin 30 = -50

250 = Ai + Bi = 100 * .866 + Bi
250 = 86.6 + Bi
Bi = 163

V^2 = 50^2 +163^2
V = 171

tan theta = -50/163 = -17 deg

so c