Three identical spherical balls A, B and C are placed on a table as shown in the figure along a straight line. B and C are at rest initially. The ball A hits B head on with a speed of 10 ms-1 . Then after all collisions (assumed to be elastic) A and B are brought to rest and C takes off with a velocity of

Question

Three identical spherical balls A, B and C are placed on a table as shown in the figure along a straight line. B and C are at rest initially. The ball A hits B head on with a speed of 10 ms-1 . Then after all collisions (assumed to be elastic) A and B are brought to rest and C takes off with a velocity of (A)  5 ms-1 (B)  10 ms-1 (C)  2.5 ms-1 (D)  7.5 ms-1

Tardigrade Admin · Accepted Answer

Here, u1=10, m1=m, m2=m, u2=0 u1=10 m / s v2=[(m2-m1/m1+m2)] u2+(2 m1 u1/m1+m2) =(2 × m × 10/2 m)=10 m / s Similarly, for B and C ⇒ v3=10 m / s

$5 m s^{- 1}$

$10 m s^{- 1}$

$2.5 m s^{- 1}$

$7.5 m s^{- 1}$

Here, $u_{1} = 10, m_{1} = m, m_{2} = m, u_{2} = 0$
$u_{1} = 10 m / s$
$v_{2} = [\frac{m _{2} - m _{1}}{m _{1} + m _{2}}]$
$u_{2} + \frac{2 m _{1} u _{1}}{m _{1} + m _{2}}$
$= \frac{2 \times m \times 10}{2 m} = 10 m / s$
Similarly, for $B$ and $C$
$\Rightarrow v_{3} = 10 m / s$

5ms−1

10ms−1

2.5ms−1

7.5ms−1

Here, u1​=10,m1​=m,m2​=m,u2​=0 u1​=10m/s v2​=[m1​+m2​m2​−m1​​] u2​+m1​+m2​2m1​u1​​ =2m2×m×10​=10m/s Similarly, for B and C ⇒v3​=10m/s

$5 m s^{- 1}$

$10 m s^{- 1}$

$2.5 m s^{- 1}$

$7.5 m s^{- 1}$

Here, $u_{1} = 10, m_{1} = m, m_{2} = m, u_{2} = 0$
$u_{1} = 10 m / s$
$v_{2} = [\frac{m _{2} - m _{1}}{m _{1} + m _{2}}]$
$u_{2} + \frac{2 m _{1} u _{1}}{m _{1} + m _{2}}$
$= \frac{2 \times m \times 10}{2 m} = 10 m / s$
Similarly, for $B$ and $C$
$\Rightarrow v_{3} = 10 m / s$