A boy of mass 45kg sits 109cm to the left of the seesaw. Another boy of mass 29000g wants to balance the seesaw. At what distance he needs to sit?

As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arranged side by side so that they are parallel to each other. when you push the platform, you compress the springs. you do an amount of work of 79.0 j when you compress the springs a distance of 0.230 m from their uncompressed length. (a) what magnitude of force must you apply to hold the platform in this position? (b)how much additional work must you do to move the platform a distance 0.230 m farther? (c) what maximum force must you apply to move the platform a distance 0.230 m farther?

Mechanical energy is when the amount of kinetic and potential energies added together remains the same. conserved created lost

If anyone who can me with this hw? i would really appreciate it