Newton's Third Law states that forces always come in pairs. Which statement best describes these pairs?

Every force eventually cancels itself out over time If A exerts a force on B, then B exerts an equal and opposite force on A Action forces are always larger than reaction forces A reaction force only appears if the object moves

You push against a wall with a force of 50 N. How much force does the wall exert back on you?

0 N — the wall doesn't move so it cannot exert a force Less than 50 N — walls can only partially push back 50 N, directed away from the wall More than 50 N — the wall is harder than your hand

A rocket in space fires its engine by expelling gas backward. Why does the rocket move forward?

The exhaust gas pushes against the air behind the rocket, propelling it forward The rocket pushes gas backward; by Newton's Third Law, the gas pushes the rocket forward with an equal force The engine creates more force than the gas, so there is a net forward force The hot gas expands and lifts the rocket from below

A swimmer pushes backward against the water with their hands and feet. What happens as a result?

The swimmer moves forward because water is less dense than their body The swimmer moves forward because the water in front of them is pushed away The water pushes forward on the swimmer with an equal force, propelling them forward The swimmer moves backward because the reaction force is opposite to their motion

Why don't action-reaction force pairs cancel each other out?

They do cancel — that is why objects often don't move They are not equal — the reaction is always slightly smaller They act on different objects, so they cannot cancel — each object experiences only one of the pair They cancel only when the objects are the same mass

A horse pulls a cart forward. Someone argues: 'The cart pulls the horse backward with an equal force, so they should never move.' What is wrong with this argument?

The argument is correct — paired forces do cancel and the horse-cart system never accelerates Horses are stronger than carts, so the action force is larger than the reaction The horse's hooves also push backward on the ground, and the ground pushes the horse forward — this ground-reaction force is larger than the cart's pull on the horse The cart's pull on the horse acts in the same direction as the horse's pull on the cart

You fire a gun. The bullet shoots forward and the gun kicks backward. Which best describes this as a Newton's Third Law pair?

The explosion pushes the bullet forward and also pushes the gun backward separately The gun pushes the bullet forward; the bullet pushes the gun backward with an equal force The bullet pushes the gun backward harder than the gun pushes the bullet forward The gun is pushed backward by air pressure created by the bullet's movement

A small car and a large truck collide head-on. Which experiences the greater force during the collision?

The truck, because it is heavier The car, because it is lighter and gets pushed more Both experience exactly the same force — Newton's Third Law requires it The one travelling faster experiences the greater force

Earth pulls you down with the force of gravity. Which is the correct Third Law reaction to this force?

The ground pushes you upward with a normal force You pull Earth upward with an equal gravitational force The air pushes you upward to balance gravity Your weight pulls the floor downward

A jet ski expels water backward through a nozzle at high speed, moving forward across the lake. Which other common vehicle works on exactly the same principle?

A sailing boat — both are pushed forward by an external fluid A bicycle — both use reaction forces from the ground A rocket — both propel themselves by expelling mass backward and receiving a forward reaction A glider — both move without using any fuel