Answer:
Mass of block = 6kg
wright = 6 × g = 60 N using g = 10 m/s^2 .
compression= 0.20m
spring constant =( weight / compression) =( 60/0.20) = 300 N/m .
Work done in compressing 0.20 m =( 1/2 × 300 × 0.20 × 0.20)= 6 joule.
Additional compression = 0.10 m
total compression = 0.20+ 0.10= 0.30 m.
Total work done = ( 1/2 × 300 × 0.30× 0.30) = 13.5 joule.
Hence work done in compressing from 0.20 m to 0.30 m will be = ( 13.5 - 6) = 7.5 joule.
Note :- work done in compressing a spring having spring constant K N/m by x m is equal to 1/2× (K) × X^ 2 .