A body of mass "m1" moving with uniform velocity of 40 m/s collides with another body of mass "m2" at rest and then two together begin to move with uniform velocity of 30 m/s. the ratio of their masses m1/m2 is:
Correct answer: C. 3.0
- A. 0.75
- B. 1.33
- C. 3.0
- D. 4.0
Explanation
To solve this problem, we use the law of conservation of linear momentum. Initially, only the body with mass m1 is moving, while the body with mass m2 is at rest. Therefore, the total initial momentum is (m1)(40 m/s). After the collision, both bodies move together with a velocity of 30 m/s, so the total final momentum is (m1 + m2)(30 m/s). According to the conservation of momentum: (m1)(40) = (m1 + m2)(30) Solving this equation: 40m1 = 30m1 + 30m2 10m1 = 30m2 m1/m2 = 3 Thus, the correct answer is 3.0. The other options do not satisfy the conservation of momentum equation.
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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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