A spring of negligible mass having a force constant of 10Nm^(-1) is compressed by a force to a distance of 4 cm. A block of mass 900g is free to leave the top of the spring. If the spring is released, the speed of the block is

A spring of negligible mass having a force constant of 10Nm^(-1) is co

1.	A spring of negligible mass having a force constant of 10Nm^(-1) is compressed by a force to a distance of 4 cm. A block of mass 900g is free to leave the top of the spring. If the spring is released, the speed of the block is
Answer» `11.3ms^(-1)` `13.3xx10ms^(-1)` `13.3xx10^(-2)ms^(-1)` `13.3xx10^(-3)ms^(-1)` Solution :`"We know that the potential energy of the SPRING"=1/2kx^(2)`. Here the potential energy of the spring is converted into KINETIC energy of the block. `1/2kx^(2)=1/2mv^(2)` `v^(2)=k/mx^(2)impliesv=sqrt(k/m)x` `v=sqrt((20)/(90))xx4xx10^(-2)=sqrt((100)/9)xx4xx10^(-2)=13.3xx10^(-2)ms^(-1)`