| Abstract : | Jupiter’s moon Io undergoes tidal heating due to frictional heat generated by gravitational forces applied by Jupiter and its other moons. However, the change in shape of Io is not because of balanced forces pulling Io from both sides, but unbalanced forces. Unbalanced forces are balanced by internal resistance created by Io’s own gravity and molecular structure stops the change in Io’s shape,
Students across the world are taught that balanced forces can change the shape of the body, but cannot change motion or direction. An example given to prove the point is pressing the balloon between two hands can change the shape by balanced forces. This is in direct contradiction to Newton’s first law of motion, which suggests that balanced forces cannot create any physical change as net force acting on the body should be zero.
When performing the experiment to determine the young’s modulus, different quantities of forces are applied to the metal rod and the induced strain is measured. When the forces are not in balance, it expands, up to a point. Once the forces inside the body are balanced by the forces outside the body, the rod will stop expanding. When the balloon is pushed from both sides, it will contract, till the forces inside the body are not counterbalancing the forces from outside. Once the forces are balanced, it will stop contracting further. Whenever a body is expanding or contracting, it will experience internal forces created by bond movement, which will counter the external forces to maintain the shape.
Equal and opposite forces can act on certain points of body, giving a sense of balanced forces, but are not really balanced forces. In balanced forces, all the points of the body experience net zero force.
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