According to the third law of motion when we put an object, the object pushes back on us with an equal and opposite force. If th
e object is massive truck park along the roadside, it will probably not move. A student justify this my answering that the two opposite and equal forces cancel Each Other. Comment on this logic and explain why the truck do not move?
Student's justification is not correct. Two equal and opposite force cancel each other if the act on the same body. According to the third law of motion action and reaction forces are equal and opposite but they both act on different bodies. Hence, they cannot cancel each other.
When we push a message track, then the applied force on the truck is not sufficient to overcome the force of friction between the tyres of truck and ground, hence, truck does not move.
