A block of $2 kg$ is hanging over a smooth string. The other end of the string is pulled by a constant force $F=40N$.The kinetic energy of the particle increases $40 \;J$ in a given interval of time. then $(g=10 m/s^2)$

Question

a) Tension in string is $45 \;N$ b) displacement of the block in the given interval of time is 2m c) Work done by gravity is $-20 \;J$ d) Work done by tension is $80 \;J$