Find the acceleration of $B$.
$\frac{a \sin \alpha_1}{\cos \alpha_2}$
$\frac{\operatorname{acos} \alpha_1}{\cos \alpha_2}$
$\frac{ a \cos \alpha_2}{\cos \alpha_1}$
$\frac{\cos \alpha_1}{\cos \alpha_2}$
Figure shows a boy on a horizontal platform $A$ on a smooth horizontal surface, holding a rope attached to a box $B$ . Boy pulls the rope with a constant force of $50\ N$ . (boy does not slip over the platform). The combined mass of platform $A$ and boy is $250\ kg$ and that of box $B$ is $500\ kg$ . The velocity of $A$ relative to the box $B$ , $5\ s$ after the boy on $A$ begins to pull the rope, will be ............ $m/s$
Two blocks of same mass $(4\ kg)$ are placed according to diagram. Initial velocities of bodies are $4\ m/s$ and $2\ m/s$ and the string is taut. Find the impulse on $4\ kg$ when the string again becomes taut .......... $N-s$
In the arrangement shown in figure $a _{1}, a _{2}, a _{3}$ and $a _{4}$ are the accelerations of masses $m _{1}, m _{2}, m _{3}$ and $m _{4}$ respectively. Which of the following relation is true for this arrangement?
Find the velocity of the hanging block if the velocities of the free ends of the rope are as indicated in the figure.
Three blocks of masses $m_1=4 \,kg , m_2=2 \,kg , m_3=4 \,kg$ are connected with ideal strings passing over a smooth. massless pulley as shown in figure. The acceleration of blocks will be ......... $m / s ^2$ $\left(g=10 \,m / s ^2\right)$