Question 123: Centre of Mass and Rotational Motion

Question

An object of mass m1 collides with another object of mass m2, which is at rest. After the collision the objects move with equal speeds in opposite direction. The ratio of the masses m2 : m1 is :

Accepted Answer

Before collision
After collision,
Applying momentum conservation,
m
1
v
1
= m
2
v $$-$$ m
1
v ..... (1)
As collision is elastic,
$$ 	herefore $$ e = 1
$$ \Rightarrow $$ $${{v - ( - v)} \over {0 - {v_1}}} = 1$$
$$ \Rightarrow $$ v
1
= 2v ..... (2)
Put value of v
1
in equation (1),
m
1
(2v) = (m
2
$$-$$ m
1
)v
$$ \Rightarrow $$ 2m
1
= m
2
$$-$$ m
1
$$ \Rightarrow $$ 3m
1
= m
2
$$ \Rightarrow $$ $${{{m_2}} \over {{m_1}}} = {3 \over 1}$$

Answer

1 : 1

Answer

3 : 1

Answer

2 : 1

Answer

1 : 2

Centre of Mass and Rotational Motion

An object of mass m1 collides with another object of mass m2, which is at rest. After the collision the objects move with equal speeds in opposite direction. The ratio of the masses m2 : m1 is :

Choose the correct answer: