Form 4 Momentum

You should have found, in part (a) that the speed of the 0.5 kg mass is 39.62 m/s and that of the 1 kg mass is 30.69 m/s
Use conservation of momentum along the direction parallel to the motion of the 1 kg mass1 x 30.69 + 0.5 x 39.62cos(40) = 1.5 x v'where v' is the velocity of the 1.5 kg mass along the direction parallel to the motion of the 1 kg mass
hence, v' = 30.58 m/s

Use conservation of momentum along the direction perpendicular to the motion of the 1 kg mass,

0.5 x 39.62sin(40) = 1.5v"
where v" is the velocity of the 1.5 kg mass along the direction perpendicular to the motion of the 1 kg mass
hence, v" = 8.49 m/s

velocity of 1.5 kg mass = square-root[8.49^2 + 30.58^2] m/s = 31.74 m/sLet a be the acute angle at which the velocity of the 1.5 kg mass makes with the line parallel to the motion of the 1 kg mass,
hence, tan(a) = 8.49/30.58
a = 15.52 degrees
Hence, direction of 1.5 kg mass measured from the direction of motion of the 1 kg mass = (180 - 15.52) degrees = 164.5 degrees.
Distance travelled by the 1.5 kg mass= (1/2).(1.5).(31.74)^2/[0.4 x 1.5g] m = 128.4 m
Direction