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three masses collide at the same time and stick together. The first mass m 1 =5

ID: 1367538 • Letter: T

Question

three masses collide at the same time and stick together. The first mass m1=5 kg is moving in the positive x-direction at an initial speed of 25 m/s. The second mass m2=12kg is initially moving in the negative y-direction with a speed of 18.0 m/s . The third mass m3=20 kg is initially moving at 30° above the negative x-axis at 10.0 m/s.

What is the final speed, vf, and direction, , ( please indicate the angle from the x- axis) of combined masses after the collision? Draw a picture, free body diagram, and break down off axis vectors.

Please help with this problem thanks :)

Explanation / Answer

take the components along x and y axis

from the conservation of momentum

m1v1x+m2v2x+m3v3x=(m1+m2+m3)*vx

v=m1v1x+m2v2x+m3v3x/(m1+m2+m3)

vx=5*25+12*0+20*cos150/37

vx=2.91 m/sec

vy=m1v1y+m2v2y+m3v3y/(m1+m2+m3)

vy=5*0+12*18+20*sin150/37

vy=6.108 m/sec

vf=sqrt(vx^2+vy^2)

vf=6.766 m/sec

direction

theta=tan^-1(vy/vx)

theta=64.53 from the positive x-axis