Newton's third law Knowledge-Based Download PDF

Questions

1. 1.

   According to Newton's third law of motion, which statement correctly describes the chronological relationship between an action force and its corresponding reaction force?

   • A) The action force acts first as the primary cause, followed by the reaction force with a slight time delay.
   • B) The reaction force appears only after the action force reaches its peak magnitude.
   • C) The action and reaction forces act simultaneously, beginning and ending at the exact same instant.
   • D) The reaction force persists for a short duration after the action force ceases to restore balance.
2. 2.

   Under which conditions does Newton's third law of motion apply to the mutual interaction between two objects?

   • A) At all times, regardless of whether the objects are at rest, moving at constant velocity, or accelerating
   • B) Only when the objects are at rest or moving with constant velocity in an equilibrium state
   • C) Only when the interacting objects have identical masses and maintain direct physical contact
   • D) Only when the net external force acting on the combined two-object system is zero
3. 3.

   According to Newton's third law of motion, under what circumstances can an isolated force exist in nature without an accompanying reaction force?

   • A) When an object moves at a constant velocity in a complete vacuum
   • B) When the net force acting on an object is equal to zero
   • C) When a force acts across empty space without physical contact
   • D) Under no circumstances, because every force is an interaction between two entities
4. 4.

   When an athlete sprints forward on a level running track, their shoes push horizontally backward against the ground. According to Newton's third law of motion, what is the reaction force to this backward push?

   • A) The downward normal force exerted by the track on the athlete
   • B) The forward inertia developed by the athlete's accelerating body
   • C) The forward frictional force exerted by the track on the athlete's shoes
   • D) The backward resistive force exerted by the air on the athlete's body
5. 5.

   A student pushes horizontally against a rigid, stationary wall with a force of 60 N. According to Newton's third law of motion, what force does the wall exert on the student?

   • A) A force of 0 N, because an inanimate, stationary wall cannot exert a force
   • B) A force of 60 N directed horizontally away from the wall
   • C) A force of less than 60 N, because the wall does not move or accelerate
   • D) A vertical force of 60 N supporting the student against gravity
6. 6.

   A rocket operating in deep space accelerates forward by expelling exhaust gases out of its nozzle. According to Newton's third law of motion, which entity exerts the forward force that causes this acceleration?

   • A) The vacuum of space, which pulls the rocket forward toward regions of lower pressure
   • B) The surrounding interstellar medium, which provides a physical surface for the exhaust to push against
   • C) The expelled exhaust gases, which push forward on the rocket with a force equal in magnitude to the force pushing them backward
   • D) The unburned propellant inside the fuel tanks, which shifts forward as the mass of the rocket decreases
7. 7.

   Why do the two forces in a Newton's third law action-reaction pair never cancel each other out to produce an equilibrium state?

   • A) They act on two different interacting objects rather than on a single object.
   • B) They act sequentially one after the other rather than simultaneously.
   • C) One force is always slightly larger in magnitude whenever acceleration occurs.
   • D) One force represents a contact interaction while the other is always a non-contact field force.
8. 8.

   During a collision between a heavy freight truck and a small passenger car, how does the magnitude of the force exerted by the truck on the car compare to the magnitude of the force exerted by the car on the truck?

   • A) The truck exerts a greater force because it has significantly more mass.
   • B) The truck exerts a greater force because it carries greater momentum into the collision.
   • C) The two forces are equal in magnitude regardless of the masses or velocities of the vehicles.
   • D) The car exerts a greater force because it undergoes a much larger acceleration during the impact.
9. 9.

   A book rests motionless on a flat, horizontal table. What is the Newton's third law reaction force to the downward gravitational force exerted by the Earth on the book?

   • A) The upward gravitational force exerted by the book on the Earth
   • B) The upward normal force exerted by the table on the book
   • C) The downward contact force exerted by the book on the table
   • D) The upward gravitational force exerted by the table on the book
10. 10.

    According to Newton's third law of motion, which of the following statements correctly describes an action-reaction force pair?

    • A) They act on two different interacting bodies with equal magnitudes and opposite directions.
    • B) They act on the same body in opposite directions, resulting in zero net force on that body.
    • C) They act on two different bodies, but the larger mass always exerts a greater magnitude of force.
    • D) They act on the same body, with the reaction force occurring slightly after the action force begins.