an unstretched hanging spring is 50cm long. suspending a 100N weight from it makes its lenght 60cm. Adding another 100N weight will make the spring --

60cm, 70 cm, 80 cm, 100 cm, or 120 cm.

No idea how they came up with any of the five ??? My answer was different!

Please help!

1 answer

The amount of stretching is proportional to the weight applied. That's called Hooke's law.

Since 100N stretches the spring 10 cm, 200 N will stretch it 20 cm. Add that to the original unstretched length.

50 + 20 = ___ cm