Why is it dangerous*btw.....And because you can easily crash into another vehicle also because it's just plain stupid to jump anyway ...
Therefore, if the block moves from its position of maximum spring stretch to maximum spring compression in 0.25 s, the time required for a full cycle is twice as much; T = 0.5 s.
When we shake a mango tree, the mangoes fall down. It is because when we shake the tree, the mango tend to be rest due to inertia where as the branches are in motion. That is why the mangoes tend to be at rest due to inertia where as the branches are in the motion.