The general effort force equation for block and tackle to raise or pull a load can be expressed as
<span><span>S=<span>F/<span>μn</span></span></span>
</span>
where
<span>S
</span> is the effort force,
<span>F
</span> is the load force (often the weight of the object to be moved),
<span>μ
</span> is the mechanical efficiency of the system (1 in an ideal, massless, frictionless system of pulleys), and
<span>n
</span> is the number of ropes between the sets of pulleys.
The correct choice is :
The final momentum of the bullet/block is equal to the initial momentum of the bullet.
initially the block was at rest , hence
initial momentum of the block = 0
so total initial momentum was simply equal to initial momentum of bullet only.
after collision , the bullet gets embedded in the block , and hence both block-bullet move together at common velocity . according to conservation of momentum , momentum remains conserved in any type of collision.
so final momentum of bullet-block system = initial momentum of bullet
"Electrostatic forces are attractive or repulsive forces between particles that are caused by their electric charges."