Question

You are pushing a wagon filled with lots of donations for the ACHS Food Drive. As you do this, the wagon exerts an equal force (pushing back) on you. Does this mean that these forces cancel out, which would make acceleration impossible? Why or why not? (Hint: we know it doesn’t make acceleration impossible, since we know that it’s possible to push objects and have them move).

Answer 1

Answer:

(a) You have been provided with 10 Ω wire which is stretched to thrice its original

length calculate:

(i) the new resistance

(ii) the current flowing through the new wire if 200V is applied across it. [3]

(b) A ray of light PQ is incident normally on the hypotenuse of a isosceles right A

angled prism ABC as shown in the adjoining figure:

(i) Copy the diagram and complete the path of the ray PQ till it emerges from

the prism.

Explanation:

Answer 2

Answer:

If you have ever stubbed your toe, you have noticed that although your toe initiates the impact, the surface that you stub it on exerts a force back on your toe. Although the first thought that crosses your mind is probably “ouch, that hurt” rather than “this is a great example of Newton’s third law,” both statements are true.

This is exactly what happens whenever one object exerts a force on another—each object experiences a force that is the same strength as the force acting on the other object but that acts in the opposite direction. Everyday experiences, such as stubbing a toe or throwing a ball, are all perfect examples of Newton’s third law in action.

Newton’s third law of motion states that whenever a first object exerts a force on a second object, the first object experiences a force equal in magnitude but opposite in direction to the force that it exerts.

Newton’s third law of motion tells us that forces always occur in pairs, and one object cannot exert a force on another without experiencing the same strength force in return. We sometimes refer to these force pairs as action-reaction pairs, where the force exerted is the action, and the force experienced in return is the reaction (although which is which depends on your point of view).

Newton’s third law is useful for figuring out which forces are external to a system. Recall that identifying external forces is important when setting up a problem, because the external forces must be added together to find the net force.