Question

A mass $A\left(600gm\right)$ is placed on a smooth table with a string attached to it. The string goes over a frictionless pulley and is connected to another mass $B\left(100gm\right)$. At $t=0$, the mass $A$ is at a distance of $100cm$ from the end and moving with a speed of $90cm/s$ towards left. After what time and with what speed will the mass $A$ reach the pulley at the right edge of the table?

Answer 1

R.E.F image

$M_B=100gm$

$m_a=6m_B$

$a=\frac{m_{B}g}{m_a+m_B}=\frac{1}{7}\left(10\right)m/s^2=\frac{1000}{7}cm/s^2$

$\mu =-90cm/s$

$d=100cm$

$d=Ut+\frac{1}{2}a{t}^2$

$100=-90t+\frac{1}{2}\frac{1000}{7}{t}^2$

$t=1.97sec\approx 2sec$

$v=\mu +at$

$v=-90+\frac{1000}{7}\left(1.97\right)$

$v=191.42cm/sec$