What subatomic particle identified this atom

Aregular polygon has angkes of size 150° each. how many side has the polygon

Aspring is used to stop a 50-kg package which is moving down a 20º incline. the spring has a constant k = 30 kn/m and is held by cables so that it is initially compressed 50 mm. knowing that the velocity of the package is 2 m/s when it is 8 m from the spring and neglecting friction, determine the maximum additional deformation of the spring in bringing the package to rest.

If we compare the force of gravity to strong nuclear force, we could conclude that