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Name Section Date Lab VIII Collisions in One and Two Dimensions Prelab 1. What i

ID: 1790255 • Letter: N

Question

Name Section Date Lab VIII Collisions in One and Two Dimensions Prelab 1. What is momentum? 2. State the law of conservation of momentum. 3. A 20 000-kg railroad car, moving with a speed of 0.08 m/s is struck from behind by another 32 000-kg railroad car moving along the same line with a speed of 0.12 m/s. If they stick together after the collision, what is their velocity? 4. A ball of mass 2 kg is traveling north with a velocity of 6 m/s when it collides with an identical ball that is at rest. After the collision, one of the ball moves off with a velocity of 2 m/s at an angle of 30° east of north. Find the velocity of the other ball.

Explanation / Answer

1. momentum is a measurable quanlity of a moving body , whose quantity ios defined as producto f mass of body to its velocity

2. conservation of meomentum states that in absense of any external force, the momentum of the system does not change

3. given, m = 20,000 kg

u = 0.08 m/s

M = 32,000 kg

v = 0.12 m/s

let final velocity after they stick together be V

then form conservation of momentum

mu + Mv = (M + m)V

20,000*0.08 + 32000*0.12 = (20,000 + 32,000)V

V = 0.1046 m/s

4. m = 2 kg

u = 6 j m/s ( i and j are unit vectors in east and north directions respectively)

final speed of balls be v1 and v2

v1 = 2(sin(30)i + cos(30)j)

so form conservation of momentum

mu = m(v1 + v2)

6j = 2(sin(30)i + cos(30)j) + v2

v2 = -i + 4.267j

|v2| = 4.383 m/s

direction = 13.189 deg west of north