8. My Notes Ask Your Teach 0/2 points I Previous Answers A 80 kg man is ice-skat

Question

8. My Notes Ask Your Teach 0/2 points I Previous Answers A 80 kg man is ice-skating due north with a velocity of 6.0 m/s when he collides with a 33 kg child. The man and child stay together and have a velocity of 3.0 m/s at an angle of 35° north of due east immediately after the collision (a) What is the magnitude of the child's velocity just before the collision? 10.26 (b) What is the direction of the child's velocity just before the collision? 35- x "(south of east) Additional Materials Section 9.1

Explanation / Answer

here,

mass of man , m1 = 80 kg

initial velocity of man , u1 = 6 m/s j

mass of child , m2 = 33 kg

final speed , v = 3 * ( cos(theta) i + sin(theta) j) m/s

v = 2.46 i m/s + 1.72 j m/s

let the initial velocity of child be (u2x i + u2y j) m/s

using conservation of momentum

m1 * u1 + m2 * u2 = (m1 + m2) * v

80 * 6 m/s j + 33 * ( u2x i + u2y j) = ( 80 + 33) * (2.46 i m/s + 1.72 j m/s)

u2x i + u2y j = 8.42 i m/s - 8.66 j m/s

a)

the magnitude of child's velocity , |v| = sqrt(u2x^2 + u2y^2) = 12.1 m/s

b)

theta = arctan(8.66/8.42) = 45.8 degree

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