If a spring is stretched to twice the lengtj of its equilibrium position, by what factor does the energy stored in the spring change?

Explain vector addition, triangle method and parallelogram method

While goofing off at the ice skating rink, a student takes off her shoes and places each of them on the ice. her friend, a hockey player, then shoots a hockey puck at each shoe. the first puck immediately comes to rest after it collides with the left shoe. the second puck rebounds after it collides with the right shoe. if each hockey puck has the same incoming speed, which shoe has greater speed after the collision? the right shoe. both shoes have the same speed. the left shoe.

A2k pendulum has a speed of 1 m/s at a height of 1/2 meter