a block is held 1.3m above a spring and is dropped.The spring compresses 6cm before sending the ball into the air. How fast is the ball going when it hits the spring? What is the spring constant? How high in the air does the ball go after hitting the spring?

Answer 1

Can you calculate how fast an object is going after falling Y 1.3 m? Sure you can. Try using conservation of energy.
M g Y = (1/2) M V^2

For the spring constant k,

(1/2) M V^2 + M g X = (1/2) kX^2
(the energy stored in the spring when motion stips). Cancel out the M's and solve for k

Since there is no friction assumed, the ball should bounce back to its original height