A body of mass $$2 kg$$ makes an elastic collision with a second body at rest and continues to move in the original direction but with one fourth of its original speed. What is the mass of the second body?
Two particles of masses $${m_1}$$ and $${m_2}$$ in projectile motion have velocities $${{\vec v}_1}$$ and $${{\vec v}_2}$$ respectively at time $$t = 0.$$ They collide at time $${t_0.}$$ Their velocities become $${{\vec v}_1}'$$ and $${{\vec v}_2}'$$ at time $$2{t_0}$$ while still moving in the air. The value of $$\left| {\left( {{m_1}{{\vec v}_1}' + {m_2}{{\vec v}_2}'} \right) - \left( {{m_1}{{\vec v}_1} + {m_2}{{\vec v}_2}} \right)} \right|$$ is
A.
zero
B.
$$\left( {{m_1} + {m_2}} \right)g{t_0}$$
C.
$$\frac{1}{2}\left( {{m_1} + {m_2}} \right)g{t_0}$$
Two blocks of masses $$10kg$$ and $$4kg$$ are connected by a spring of negligible mass and placed on a frictionless horizontal surface. An impulse gives a velocity of $$14 m/s$$ to the heavier block in the direction of the lighter block. The velocity of the centre of mass is
A ball of mass $$0.2kg$$ rests on a vertical post of height $$5m.$$ A bullet of mass $$0.01kg,$$ traveling with a velocity $$V m/s$$ in a horizontal direction, hits the centre of the ball. After the collision, the ball and bullet travel independently. The ball hits the ground at a distance of $$20m$$ and the bullet at a distance of $$100m$$ from the foot of the post. The velocity $$V$$ of the bullet is
A particle of mass $$m$$ is projected from the ground with an initial speed $${u_0}$$ at an angle $$\alpha $$ with the horizontal. At the highest point of its trajectory, it makes a completely inelastic collision with another identical particle, which was thrown vertically upward from the ground with the same initial speed $${u_0}.$$ The angle that the composite system makes with the horizontal immediately after the collision is