Equal and Opposite Forces - Middle School Physical Science
Card 1 of 25
What type of force usually forms the action–reaction pair in a collision (ignoring gravity)?
What type of force usually forms the action–reaction pair in a collision (ignoring gravity)?
Tap to reveal answer
Contact force (normal/impact force). Direct physical contact creates the force pair.
Contact force (normal/impact force). Direct physical contact creates the force pair.
← Didn't Know|Knew It →
Which option is correct: action–reaction forces cancel each other on one object, or act on different objects?
Which option is correct: action–reaction forces cancel each other on one object, or act on different objects?
Tap to reveal answer
They act on different objects, so they do not cancel on one object. Can't cancel because they're on separate objects.
They act on different objects, so they do not cancel on one object. Can't cancel because they're on separate objects.
← Didn't Know|Knew It →
What does “opposite in direction” mean for collision forces?
What does “opposite in direction” mean for collision forces?
Tap to reveal answer
The forces point in opposite directions along the same line. Forces are 180° apart but along the same action line.
The forces point in opposite directions along the same line. Forces are 180° apart but along the same action line.
← Didn't Know|Knew It →
What does “equal in magnitude” mean for collision forces?
What does “equal in magnitude” mean for collision forces?
Tap to reveal answer
The forces have the same size (same numerical value). Magnitude refers to the absolute value or size.
The forces have the same size (same numerical value). Magnitude refers to the absolute value or size.
← Didn't Know|Knew It →
Identify where the action and reaction forces act during a collision: on the same object or different objects?
Identify where the action and reaction forces act during a collision: on the same object or different objects?
Tap to reveal answer
On different objects. Newton's third law requires forces act on separate objects.
On different objects. Newton's third law requires forces act on separate objects.
← Didn't Know|Knew It →
What is an action–reaction force pair during a collision?
What is an action–reaction force pair during a collision?
Tap to reveal answer
Two forces on different objects that are equal and opposite. Each object exerts a force on the other during contact.
Two forces on different objects that are equal and opposite. Each object exerts a force on the other during contact.
← Didn't Know|Knew It →
Identify the reaction force to “the wall pushes on your hand” during a collision with a wall.
Identify the reaction force to “the wall pushes on your hand” during a collision with a wall.
Tap to reveal answer
Your hand pushes on the wall. Newton's third law: wall and hand exchange forces.
Your hand pushes on the wall. Newton's third law: wall and hand exchange forces.
← Didn't Know|Knew It →
If object $A$ collides with $B$ for $0.10,\text{s}$, is the time interval of the force on $A$ equal to that on $B$?
If object $A$ collides with $B$ for $0.10,\text{s}$, is the time interval of the force on $A$ equal to that on $B$?
Tap to reveal answer
Yes, both forces act over the same time interval. Contact duration is the same for both objects.
Yes, both forces act over the same time interval. Contact duration is the same for both objects.
← Didn't Know|Knew It →
If two skaters collide and exert equal and opposite forces, which skater has the larger acceleration?
If two skaters collide and exert equal and opposite forces, which skater has the larger acceleration?
Tap to reveal answer
The skater with the smaller mass. $F=ma$, so smaller mass means larger acceleration.
The skater with the smaller mass. $F=ma$, so smaller mass means larger acceleration.
← Didn't Know|Knew It →
A student says, “The bigger object exerts a bigger force in a collision.” Identify if this is correct or incorrect.
A student says, “The bigger object exerts a bigger force in a collision.” Identify if this is correct or incorrect.
Tap to reveal answer
Incorrect. Forces are always equal; mass affects acceleration, not force.
Incorrect. Forces are always equal; mass affects acceleration, not force.
← Didn't Know|Knew It →
If a bat exerts $200,\text{N}$ on a ball, what is the force of the ball on the bat?
If a bat exerts $200,\text{N}$ on a ball, what is the force of the ball on the bat?
Tap to reveal answer
$200,\text{N}$ opposite the bat's force. Newton's third law: equal forces in opposite directions.
$200,\text{N}$ opposite the bat's force. Newton's third law: equal forces in opposite directions.
← Didn't Know|Knew It →
If a truck hits a car and the truck exerts $5000,\text{N}$ on the car, what force does the car exert on the truck?
If a truck hits a car and the truck exerts $5000,\text{N}$ on the car, what force does the car exert on the truck?
Tap to reveal answer
$5000,\text{N}$ in the opposite direction. Newton's third law applies regardless of object sizes.
$5000,\text{N}$ in the opposite direction. Newton's third law applies regardless of object sizes.
← Didn't Know|Knew It →
If object $A$ pushes on object $B$ with $30,\text{N}$ to the right, what is $F_{B\to A}$?
If object $A$ pushes on object $B$ with $30,\text{N}$ to the right, what is $F_{B\to A}$?
Tap to reveal answer
$30,\text{N}$ to the left. Newton's third law: equal magnitude, opposite direction.
$30,\text{N}$ to the left. Newton's third law: equal magnitude, opposite direction.
← Didn't Know|Knew It →
What law states that forces between interacting objects are equal in magnitude and opposite in direction?
What law states that forces between interacting objects are equal in magnitude and opposite in direction?
Tap to reveal answer
Newton's third law of motion. States that every action has an equal and opposite reaction.
Newton's third law of motion. States that every action has an equal and opposite reaction.
← Didn't Know|Knew It →
Which quantity is always equal for the two forces in a collision: mass, acceleration, or force magnitude?
Which quantity is always equal for the two forces in a collision: mass, acceleration, or force magnitude?
Tap to reveal answer
Force magnitude. Newton's third law guarantees equal force magnitudes.
Force magnitude. Newton's third law guarantees equal force magnitudes.
← Didn't Know|Knew It →
What is the name of the force pair two objects exert on each other during a collision?
What is the name of the force pair two objects exert on each other during a collision?
Tap to reveal answer
An action–reaction force pair. Newton's third law creates paired forces during interactions.
An action–reaction force pair. Newton's third law creates paired forces during interactions.
← Didn't Know|Knew It →
Which statement is correct: forces in a collision are equal and opposite, or accelerations are equal and opposite?
Which statement is correct: forces in a collision are equal and opposite, or accelerations are equal and opposite?
Tap to reveal answer
Forces are equal and opposite; accelerations may differ. Newton's third law applies to forces; $F=ma$ shows accelerations depend on mass.
Forces are equal and opposite; accelerations may differ. Newton's third law applies to forces; $F=ma$ shows accelerations depend on mass.
← Didn't Know|Knew It →
What equation relates the collision forces on objects $A$ and $B$ using Newton's third law?
What equation relates the collision forces on objects $A$ and $B$ using Newton's third law?
Tap to reveal answer
$F_{A o B} = -F_{B o A}$. Newton's third law expressed mathematically for collision forces.
$F_{A o B} = -F_{B o A}$. Newton's third law expressed mathematically for collision forces.
← Didn't Know|Knew It →
What is Newton's third law of motion in words for a collision between two objects?
What is Newton's third law of motion in words for a collision between two objects?
Tap to reveal answer
For every force, there is an equal-magnitude, opposite-direction force. This fundamental principle governs all interactions between objects.
For every force, there is an equal-magnitude, opposite-direction force. This fundamental principle governs all interactions between objects.
← Didn't Know|Knew It →
What does the negative sign mean in $F_{A o B} = -F_{B o A}$?
What does the negative sign mean in $F_{A o B} = -F_{B o A}$?
Tap to reveal answer
The forces act in opposite directions. Negative indicates opposite direction, not lesser magnitude.
The forces act in opposite directions. Negative indicates opposite direction, not lesser magnitude.
← Didn't Know|Knew It →
Identify where the action and reaction forces act: on the same object or on different objects?
Identify where the action and reaction forces act: on the same object or on different objects?
Tap to reveal answer
They act on different objects. A acts on B while B acts on A, preventing cancellation.
They act on different objects. A acts on B while B acts on A, preventing cancellation.
← Didn't Know|Knew It →
Which option is correct: action–reaction forces cancel each other on one object, or they do not cancel on one object?
Which option is correct: action–reaction forces cancel each other on one object, or they do not cancel on one object?
Tap to reveal answer
They do not cancel on one object. Forces act on separate objects, so they cannot cancel.
They do not cancel on one object. Forces act on separate objects, so they cannot cancel.
← Didn't Know|Knew It →
What relationship between accelerations follows from equal collision forces if masses differ?
What relationship between accelerations follows from equal collision forces if masses differ?
Tap to reveal answer
$a ext{ is larger for the smaller mass.}$. From $F=ma$: same force but smaller mass yields larger acceleration.
$a ext{ is larger for the smaller mass.}$. From $F=ma$: same force but smaller mass yields larger acceleration.
← Didn't Know|Knew It →
If object $A$ pushes object $B$ with $50,\text{N}$ to the right, what is $F_{B\to A}$?
If object $A$ pushes object $B$ with $50,\text{N}$ to the right, what is $F_{B\to A}$?
Tap to reveal answer
$50,\text{N}$ to the left. Newton's third law: equal magnitude, opposite direction.
$50,\text{N}$ to the left. Newton's third law: equal magnitude, opposite direction.
← Didn't Know|Knew It →
If $F_{A\to B} = -12,\text{N}$ (left), what is $F_{B\to A}$?
If $F_{A\to B} = -12,\text{N}$ (left), what is $F_{B\to A}$?
Tap to reveal answer
$+12,\text{N}$ (right). Opposite sign indicates opposite direction with same magnitude.
$+12,\text{N}$ (right). Opposite sign indicates opposite direction with same magnitude.
← Didn't Know|Knew It →