A ball of mass 2 kg traveling at 8 ms-1 strikes a ball of mass 4 kg traveling at 2 ms-1. Both balls are moving along the same straight line as shown. After the collision, both balls move at the same velocity v. What is the magnitude of the velocity v?
Correct answer: A. 4 ms-1
- A. 4 ms-1
- B. 5 ms-1
- C. 6 ms-1
- D. 8 ms-1
- E. 10 ms-1
Explanation
Option A is correct when we apply the law of conservation of momentum as mv= m1v1+ m2v2 m=m1+m2 = 2+4 = 6kg. m1 = 2kg, m2= 4kg , v1= 8ms-1, v2=2ms-1 Thus , 6xV= 2x8 + 4x2 V= (16+8)/6=4ms-1 Hence, all other options are incorrect.
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Displacement, velocity and acceleration describe motion, including the horizontal and vertical components of projectile motion. The chapter connects these quantities with Newton's laws, momentum and impulse, then applies conservation of momentum to collisions, distinguishing elastic collisions from inelastic ones.
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