You hold one end of a rope and pull horizontally with a force of 65N. Calculate the tension in the rope if the other end is:
a) Tied to a wall.
b) Held by a friend who is pulling with a force of 65N in the opposite direction
a) If the other end of the rope is tied to a wall, the tension in the rope will also be 65N. This is because the wall provides an equal and opposite reaction force to the force applied by you. Newton's third law states that for every action, there is an equal and opposite reaction.
b) If the other end of the rope is held by a friend who is pulling with a force of 65N in the opposite direction, the tension in the rope will be the sum of the two forces. In this case, the tension in the rope will be 65N + 65N = 130N. This is because the friend's force is in the opposite direction, so the tension in the rope is the combined effect of both forces.