A `4 kg` block is on a smooth horizontal table. The block is connected to a second block of mass `1 kg` by a massless flexible taut cord that passes over a frictionless pulley. The `1 kg` block is `1m` above the floor. The two block are released from rest. With what speed does the `1 kg` block hit the ground?
.

Options

A. `4 ms^(-1)`
B. `2 ms^(-1)`
C. `8 ms^(-1)`
D. `1 ms^(-1)`

Answer

B

Explanation

Decrease in potential energy of `1kg =` increase in kinetic energy of both
`rArr 1 xx 10 xx 1=1/2 xx (4 +1)xx v^(2)`
`:. v=2 m//s`