An object on a frictionless surface is subjected to three horizontal forces: $F_1 = 25 \text{ N}$ acting due east, $F_2 = 40 \text{ N}$ acting due west, and $F_3 = 10 \text{ N}$ acting due east. What is the net force acting on the object?
$5 \text{ N, west}$
$75 \text{ N, east}$
$5 \text{ N, east}$
$65 \text{ N, west}$
A free-body diagram for a box being pushed across a rough horizontal floor at a constant velocity is shown. Which diagram is correct? (N = Normal Force, W = Weight, P = Push Force, f = Friction)
An upward arrow N and a downward arrow W of equal length. A rightward arrow P and a leftward arrow f of equal length.
An upward arrow N that is longer than a downward arrow W. A rightward arrow P and a leftward arrow f of equal length.
Only a rightward arrow P and a leftward arrow f are shown, and P is longer than f.
An upward arrow N and a downward arrow W of equal length. A rightward arrow P that is longer than a leftward arrow f.
An object is moving to the right with a constant velocity of $10 \text{ m/s}$. A force of $15 \text{ N}$ pushes it to the right and a drag force, $F_{drag}$, acts on it. What is the magnitude of the drag force?
Less than $15 \text{ N}$ but greater than $0 \text{ N}$
Greater than $15 \text{ N}$
$0 \text{ N}$
Exactly $15 \text{ N}$
A satellite is drifting in deep space, far from any significant gravitational influence, at a constant velocity. According to Newton's First Law, what is true about the satellite?
Its inertia is zero because there is no gravity.
A constant force from its thrusters is required to maintain its constant velocity.
The net force on it is zero, and it will continue to move at that velocity indefinitely.
The net force on it is zero, and it will eventually slow down and stop.
A net force of $24 \text{ N}$ is applied to a $6 \text{ kg}$ bowling ball, while an identical net force of $24 \text{ N}$ is applied to a $2 \text{ kg}$ tennis ball. Which statement accurately compares their accelerations?
Both balls accelerate at $6 \text{ m/s}^2$.
The bowling ball accelerates at $12 \text{ m/s}^2$; the tennis ball accelerates at $4 \text{ m/s}^2$.
The bowling ball accelerates at $144 \text{ m/s}^2$; the tennis ball accelerates at $48 \text{ m/s}^2$.
The bowling ball accelerates at $4 \text{ m/s}^2$; the tennis ball accelerates at $12 \text{ m/s}^2$.
A force $F$ causes a mass $m$ to accelerate at $a$. If the mass is tripled to $3m$ and the force is halved to $F/2$, what is the new acceleration, $a_{new}$?
$a_{new} = a/3$
$a_{new} = 6a$
$a_{new} = 2a/3$
$a_{new} = a/6$
An object accelerates at $3.5 \text{ m/s}^2$ when an unknown net force is applied. If the mass of the object is determined to be $8.0 \text{ kg}$, what was the magnitude of the net force?
$2.29 \text{ N}$
$28.0 \text{ N}$
$32.0 \text{ N}$
$11.5 \text{ N}$
An astronaut has a mass of $70 \text{ kg}$ on Earth. The gravitational acceleration on Mars is approximately $3.7 \text{ m/s}^2$. What are the astronaut's mass and weight on Mars?
Mass = $70 \text{ kg}$, Weight = $686 \text{ N}$
Mass = $259 \text{ kg}$, Weight = $259 \text{ N}$
Mass = $18.9 \text{ kg}$, Weight = $70 \text{ N}$
Mass = $70 \text{ kg}$, Weight = $259 \text{ N}$
A $10 \text{ kg}$ box is pushed with a horizontal force of $50 \text{ N}$ on a surface with a kinetic friction force of $20 \text{ N}$. What is the acceleration of the box?
$5.0 \text{ m/s}^2$
$3.0 \text{ m/s}^2$
$7.0 \text{ m/s}^2$
$2.0 \text{ m/s}^2$
Which statement best explains the difference between mass and weight?
Mass and weight are both measures of inertia, but weight is measured in Newtons and mass is in kilograms.
An object's weight is always greater than its mass, but they represent the same physical property.
Mass is a measure of inertia and is constant, while weight is the force of gravity and depends on location.
Mass is the force of gravity on an object, while weight is the amount of matter in it.
A heavy filing cabinet has a mass of $80 \text{ kg}$. You push on it horizontally with a force of $300 \text{ N}$, but it does not move. What is the magnitude of the static friction force acting on the cabinet? (Assume $g = 10 \text{ m/s}^2$)
$800 \text{ N}$
$500 \text{ N}$
$300 \text{ N}$
According to Newton's Third Law, when a bat hits a baseball, the force the bat exerts on the ball is equal in magnitude and opposite in direction to the force the ball exerts on the bat. Why does the ball accelerate more than the bat?
The force the bat exerts is actually slightly larger than the force the ball exerts.
The force on the ball lasts for a longer time.
The bat is moving faster than the ball initially.
The ball has much less mass than the bat, so it experiences a greater acceleration for the same force.
A $1500 \text{ kg}$ car accelerates from rest to $25 \text{ m/s}$ in $10 \text{ s}$. What is the average net force acting on the car during this time?
$37500 \text{ N}$
$600 \text{ N}$
$3750 \text{ N}$
$15000 \text{ N}$
An elevator with a mass of $800 \text{ kg}$ is being pulled upward by a cable with a tension force of $9000 \text{ N}$. What is the net force on the elevator? (Use $g = 9.8 \text{ m/s}^2$)
$7840 \text{ N, downward}$
$1000 \text{ N, upward}$
$1160 \text{ N, upward}$
$16840 \text{ N, upward}$
A swimmer pushes off a wall to accelerate forward in the water. Which of the following is the correct action-reaction pair as described by Newton's Third Law?
Action: The swimmer pushes the water backwards. Reaction: The water pushes the swimmer forwards.
Action: The swimmer's forward motion. Reaction: The water resistance (drag).
Action: The swimmer pushes the wall. Reaction: The wall pushes the swimmer.
Action: The force of gravity on the swimmer. Reaction: The buoyant force of the water on the swimmer.
An object has a weight of $120 \text{ N}$ on a planet where the acceleration due to gravity is $g_{planet}$. On Earth, where $g_{Earth} = 9.8 \text{ m/s}^2$, the same object has a weight of $196 \text{ N}$. What is the value of $g_{planet}$?
$20.0 \text{ m/s}^2$
$6.0 \text{ m/s}^2$
$12.2 \text{ m/s}^2$
$4.9 \text{ m/s}^2$
A skydiver is falling at a terminal velocity of $50 \text{ m/s}$. Their mass is $75 \text{ kg}$. Which statement correctly describes the forces acting on them? (Use $g \approx 10 \text{ m/s}^2$)
The force of gravity is $750 \text{ N}$ and the force of air resistance is $0 \text{ N}$.
The force of air resistance is $750 \text{ N}$ and the force of gravity is slightly less than $750 \text{ N}$.
The net force is $750 \text{ N}$ downwards, causing the constant velocity.
The force of gravity is $750 \text{ N}$ and the force of air resistance is also $750 \text{ N}$.
The chart shows the maximum static friction force and the kinetic friction force for an object on three different surfaces. A horizontal force of $55 \text{ N}$ is applied to the object, which has a mass of $10 \text{ kg}$, while it is on the 'Concrete' surface. What is the acceleration of the object?
$0.5 \text{ m/s}^2$
$0 \text{ m/s}^2$
$5.5 \text{ m/s}^2$
An experiment measures the acceleration of a cart of constant mass as the net force applied to it is varied. The results are shown in the bar chart. Based on the trend in the data, what would you predict the acceleration to be if the net force was $25 \text{ N}$?
$4.0 \text{ m/s}^2$
$12.5 \text{ m/s}^2$
The graph shows the relationship between the net force applied to an object and its resulting acceleration. Based on the graph, what is the mass of the object?
$2.5 \text{ kg}$
$0.4 \text{ kg}$
$4.0 \text{ kg}$
$10.0 \text{ kg}$
The velocity-time graph for a $2.0 \text{ kg}$ object is shown. What is the magnitude of the net force acting on the object between $t=2 \text{ s}$ and $t=4 \text{ s}$?
$10.0 \text{ N}$
$4.0 \text{ N}$
$6.0 \text{ N}$
$3.0 \text{ N}$
Two boxes are pushed across a frictionless floor. A $30 \text{ N}$ force pushes on a $5 \text{ kg}$ box, which in turn pushes on a $10 \text{ kg}$ box. What is the acceleration of the $10 \text{ kg}$ box?
$1.5 \text{ m/s}^2$
A person stands on a bathroom scale inside a moving elevator. The scale reads a value greater than their actual weight. Which of the following could describe the elevator's motion?
The elevator is moving downwards at a constant speed.
The elevator is accelerating upwards.
The elevator is accelerating downwards.
The elevator is moving upwards at a constant speed.
An object of mass $m$ is dropped from a great height. It eventually reaches terminal velocity. Which statement provides the best scientific explanation for this phenomenon?
As the object's speed increases, the upward force of air resistance increases until it balances the downward force of gravity, resulting in zero net force and constant velocity.
The object's mass decreases as it falls, which causes its acceleration to decrease to zero.
The object runs out of potential energy, so it stops accelerating and maintains a constant velocity.
The force of gravity on the object decreases as it falls, eventually becoming zero.
A hockey puck slides on frictionless ice at a constant velocity of $10 \text{ m/s}$. It is then hit by a hockey stick with a force of $50 \text{ N}$ in the direction of its motion. The force is applied for $0.2 \text{ s}$. What concept is primarily demonstrated by the puck continuing to move after the stick is no longer in contact?
Newton's First Law (Inertia)
Newton's Third Law (Action-Reaction)
The force of kinetic friction
The concept of weight ($W=mg$)
A $15 \text{ kg}$ crate is pushed across a horizontal floor by a horizontal force of $80 \text{ N}$. The force of kinetic friction opposing the motion is $35 \text{ N}$. Calculate the acceleration of the crate in $\text{m/s}^2$.
An elevator and its occupants have a total mass of $1200 \text{ kg}$. The elevator is accelerating downwards at $1.5 \text{ m/s}^2$. What is the tension in the supporting cable? (Use $g = 9.8 \text{ m/s}^2$)
Two boxes, Box A ($5.0 \text{ kg}$) and Box B ($10.0 \text{ kg}$), are in contact on a frictionless horizontal surface. A horizontal force of $30.0 \text{ N}$ is applied to Box A, pushing both boxes forward. What is the magnitude of the contact force that Box A exerts on Box B?
Two forces, $\vec{F}_1 = 15 , N$ acting to the right and $\vec{F}_2 = 25 , N$ acting to the left, are applied to a box. A third force, $\vec{F}_3$, also acts on the box. If the box has a mass of $5 , kg$ and accelerates to the left at $2 , m/s^2$, what is the magnitude and direction of $\vec{F}_3$?
$10 , N$ to the left
$20 , N$ to the left
$0 , N$
$10 , N$ to the right
A book is at rest on a tabletop. A student is pushing the book horizontally to the right with a force $\vec{F}_{applied}$, but the book is not moving. Which statement best describes the forces acting on the book?
The normal force, gravity, the applied force, and the force of static friction are all acting on the book, and the net force is zero.
The applied force and the force of static friction are balanced, but the vertical forces of gravity and normal force are unbalanced.
The applied force is greater than the force of static friction, but not enough to overcome the book's inertia.
The only forces acting on the book are the normal force and gravity, which are balanced.
The diagram shows four primary forces acting on a model airplane in flight. The forces are: Thrust = $50 , N$, Drag = $30 , N$, Lift = $40 , N$, and Weight = $40 , N$. Which statement correctly describes the forces and the resulting motion of the airplane?
The forces are unbalanced, and the plane accelerates horizontally in the direction of the thrust.
The forces are balanced, and the plane remains stationary in the air.
The forces are unbalanced, and the plane accelerates both upwards and in the direction of the thrust.
The forces are balanced, and the plane moves at a constant velocity.
A satellite is moving in the vacuum of deep space, far from any significant gravitational influence. Its rockets, which were providing thrust, have just shut off. Which statement best provides a scientific explanation for the satellite's subsequent motion?
It will gradually slow down and stop because an object requires a continuous force to maintain motion.
It will continue to move at a constant velocity due to its inertia, as the net force acting on it is now zero.
It will immediately stop because the force that was causing its motion is no longer present.
It will begin to travel in a large circle because circular motion is the natural state for objects in space.
A net force of $30 , N$ acts on a $500 , g$ cart. What is the acceleration of the cart?
$60 , m/s^2$
$15 , m/s^2$
$15,000 , m/s^2$
$0.017 , m/s^2$
An object accelerates at $3.0 , m/s^2$ when a net force of $12 , N$ is applied. If the net force is increased to $18 , N$, what is the new acceleration, assuming the object's mass remains constant?
$4.5 , m/s^2$
$6.0 , m/s^2$
$7.5 , m/s^2$
$2.0 , m/s^2$
An astronaut has a mass of $70 , kg$ on Earth. The acceleration due to gravity on Mars is approximately $g_{Mars} = 3.7 , m/s^2$. What is the astronaut's approximate weight on Mars?
$259 , N$
$686 , N$
$70 , N$
$18.9 , N$
A robotic rover is transported from Earth to the Moon, where the gravitational field strength is about 1/6th that of Earth. Which statement provides the most accurate scientific explanation of what happens to the rover's mass and weight?
Its mass decreases because there is less gravity, but its weight stays the same because it is the same object.
Its mass stays the same because it is an intrinsic property of the object, but its weight decreases because the gravitational force is less.
Both its mass and weight decrease by a factor of 6 because they are directly proportional to each other.
Both its mass and weight stay the same because the amount of matter in the rover has not changed.
A $10 , kg$ sled is pushed with a horizontal force of $50 , N$. It accelerates at $3 , m/s^2$ across a snowy surface. What is the magnitude of the force of friction, $\vec{F}_f$, acting on the sled?
$20 , N$
$30 , N$
$50 , N$
$80 , N$
A student applies the same constant net force to four different blocks and measures their resulting acceleration. The data is shown in the chart. Which statement provides the best scientific explanation for the observed data?
The net force was greatest on Block A, because it had the highest acceleration.
Block A has the greatest mass, because it experienced the greatest change in velocity.
Block D has the greatest mass, because for a constant net force, a larger mass results in a smaller acceleration.
All blocks have the same inertia, but the friction was different for each, resulting in different accelerations.
An experiment is conducted to measure the acceleration of a cart as the net force applied to it is varied. The mass of the cart is kept constant. The graph shows the Net Force applied vs. the resulting Acceleration. What physical quantity does the slope of the line of best fit represent?
The final velocity of the cart.
The inverse of the mass ($1/m$) of the cart.
The mass ($m$) of the cart.
The gravitational acceleration ($g$).
The velocity-time graph for a $2 , kg$ object is shown. What is the net force acting on the object during the time interval from $t=2 , s$ to $t=4 , s$?
$2 , N$
$4 , N$
$8 , N$
A $20 , kg$ crate is pushed across a floor with a horizontal force of $100 , N$. The coefficient of kinetic friction between the crate and the floor is $\mu_k = 0.4$. What is the acceleration of the crate? (Assume $g = 10 , m/s^2$)
$1.0 , m/s^2$
$5.0 , m/s^2$
$3.0 , m/s^2$
$0 , m/s^2$
A student is sitting motionless in a chair. According to Newton's Third Law, what is the reaction force to the Earth's gravitational force pulling the student down?
The floor pushing up on the chair.
The chair pushing up on the student.
The student's gravitational force pulling up on the Earth.
The student pushing down on the chair.
A car is traveling north at a constant speed of $80 , km/h$. Which of the following statements provides the best scientific explanation for the forces acting on the car?
The force from the engine pushing the car north must be greater than the forces of friction and air resistance, otherwise the car would stop.
The force from the engine pushing the car north is equal in magnitude and opposite in direction to the sum of friction and air resistance, resulting in a zero net force.
There are no significant horizontal forces acting on the car because it is moving at a constant speed and not accelerating.
The car's inertia is the forward force that overcomes friction and air resistance, keeping it at a constant speed.
A box is pulled by two ropes on a frictionless horizontal surface. One rope pulls with $40 , N$ of force to the east, and the other pulls with $30 , N$ of force to the north. What is the magnitude of the net horizontal force on the box?
$10 , N$
$1200 , N$
An elevator is accelerating upwards. Which free-body diagram best represents the forces acting on a person standing inside it, where $\vec{F}_N$ is the normal force from the elevator floor and $\vec{W}$ is the person's weight?
An upward arrow $\vec{F}_N$ and a downward arrow $\vec{W}$ of equal length.
An upward arrow $\vec{F}_N$ that is longer than the downward arrow $\vec{W}$.
A downward arrow $\vec{W}$ that is longer than the upward arrow $\vec{F}_N$.
Only a downward arrow $\vec{W}$ because gravity is the dominant force.
A magician performs a trick where they quickly pull a tablecloth out from under a set of dishes, and the dishes remain on the table. Which scientific principle provides the best explanation for why the dishes do not move with the tablecloth?
Newton's Second Law: The small force of friction applied for a short time gives the dishes very little acceleration.
The Law of Conservation of Momentum: The total momentum of the system must be conserved.
Newton's Third Law: The tablecloth pulls on the dishes, and the dishes pull back on the tablecloth with an equal force.
Newton's First Law (Inertia): The dishes have mass and therefore resist a change in their state of rest.
A constant net force $\vec{F}$ gives a mass $m_1$ an acceleration of $4 , m/s^2$. The same force $\vec{F}$ gives a mass $m_2$ an acceleration of $12 , m/s^2$. What is the ratio of the masses, $m_1/m_2$?
$4$
$1/4$
$1/3$
$3$
An object has a weight of $120 , N$ on an unknown planet where the acceleration due to gravity is $15 , m/s^2$. What is the mass of the object if it were brought to Earth (where $g \approx 9.8 , m/s^2$)?
$1800 , kg$
$12.2 , kg$
$0.82 , kg$
$8.0 , kg$
A student investigates the acceleration of a $2.5 , kg$ wooden block on a horizontal surface by applying a variable force. The data is plotted on the graph of Acceleration vs. Applied Force. Based on the graph, what is the approximate magnitude of the force of kinetic friction?
$1.6 , N$
$2.5 , N$
$6.0 , N$
$12.0 , N$
A small car and a large truck collide head-on. During the brief moment of the collision, which of the following statements provides the most accurate explanation based on Newton's Laws?
The car exerts a greater magnitude force on the truck because it experiences a much larger change in velocity.
The truck exerts a greater magnitude force on the car than the car exerts on the truck, which is why the car sustains more damage.
The truck and the car exert forces of equal magnitude on each other, but the car experiences a greater acceleration due to its smaller mass.
The net force on the car is equal to the net force on the truck, as the forces they exert on each other are an action-reaction pair.
A $5 , kg$ block is pulled up a frictionless ramp inclined at $30^\circ$ by a rope parallel to the ramp's surface. If the block accelerates up the ramp at $2 , m/s^2$, what is the tension in the rope? (Use $g=10 , m/s^2$ and $\sin(30^\circ)=0.5$)
$35 , N$
$25 , N$
$15 , N$
An object is thrown straight up into the air. It rises to a peak height and then falls back down. Which statement provides the best scientific explanation for the net force on the object at its highest point? (Ignore air resistance).
The net force is changing from upwards to downwards at this point, so it must pass through zero.
The net force is zero because the object's velocity is momentarily zero, so it is in a state of equilibrium.
The net force is upwards and equal to the initial force of the throw, which is why it stops and comes back down.
The net force is downwards and equal to the object's weight, because gravity is the only force acting on it throughout its flight.
A skydiver has jumped from a plane and has opened her parachute. After a short time, she is descending at a constant terminal velocity. Which of the following provides the best explanation of the forces at this moment?
The force of air resistance is significantly greater than the force of gravity, which is what prevents her from accelerating.
There are no forces acting on her since her velocity is constant, according to Newton's First Law.
The force of gravity is greater than the force of air resistance, which is why she continues to fall.
The upward force of air resistance and the downward force of gravity are balanced, resulting in a net force of zero and constant velocity.
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