Physics unit

Which of the following has the greatest acceleration? Each brick has the same mass and each hand applies the same amount of force. This question is similar to the rocket simulation (Figure 1.2) in the Science Object. A B C All scenarios have the same acceleration

B two hands pushing

If a force is exerted on an object, you can be sure the object will accelerate.

False. In order to figure out whether or not an object will accelerate, you must determine the net force acting on it. It's possible that the force in question is balanced out by another force, leading to zero net force and zero acceleration.

Mass is a measure of how hard something pushes back on you when you try and exert a force on it.

False. Mass is a measure of an object's inertia. As such, the number associated with mass tells you how difficult it is to change the object's motion. You can use the value of the mass in F=ma to determine what acceleration will result from a given net force.

A net, unbalanced force acting on an object will always cause the object to accelerate. That acceleration will always show up as a change in speed.

The first part of this statement is true. Net forces cause objects to accelerate. The second sentence is false. The object's acceleration might show up as a change in speed, but it could also show up as a change in direction.

Suppose you are pulling a wagon along the sidewalk. If the mass of the wagon remains the same and the acceleration of the wagon increases, that causes the force you are applying to increase.

This is sort of true and sort of false. An increase in the wagon's acceleration implies that you have increased the net force acting on it (use the teeter-totter to check this). Changing the wagon's acceleration does not, however, cause the net force to increase. Net forces cause accelerations, not the other way around.

Fill in the blanks. ____________ describes how fast and in what direction an object is moving while acceleration describes the rate at which velocity changes over ________.

Velocity, time

According to Newton's second law, if you double the unbalanced force on an object of a given mass the acceleration will be . . . Hint: Think about adding an extra power booster to increase the thrust of a rocket, how will acceleration be affected? Or think about me pushing my 3yo Nolan in the stroller twice as hard . . . What will happen to acceleration? In these situations, mass is not changing. a.Doubled b.Increased fourfold c.Increased by one-half d.Increased by one-fourt

a

In the Science Object, you watched an animation in which a tortoise won a race against a hare. Which one of the animals had a constant speed? a.tortoise b.hare c.Both the tortoise and hare d.Neither the tortoise or hare

a

In the picture, now let's assume that Track A is friction less and Track B has a high level of friction. Select the best answer. a.After the ball is dropped, it would rise higher in vertical height on Track A. b.After the ball is dropped, it would rise higher in vertical height on Track B. c.After the ball is dropped, it would rise to the same vertical height on both tracks. d.There is not enough information to answer given.

a

Same scenario as question above - What is the acceleration of the car? a.Zero - the car is not accelerating b.0.3 m/s/s c.2.0 m/s/s d.3.0 m/s/s

a

The rate at which an object travels a certain distance is known as a.Speed b.Velocity c.Momentum d.Acceleration

a

What is the average speed of a cheetah that sprints 100m in 4s? a.25 m/s b.25 m/s/s c.25 s d.25 m

a

What part of Newton's First Law does the coin in the "coin trick" video illustrate? a.Objects at rest tend to remain at rest b.Objects that are moving tend to keep moving c.To every action, there is an equal and opposed reaction d.Acceleration of an object is directly proportional to the net force exerted on the object

a

Let's put some ideas together from the first and second Science Objects on motion. Which of the following are examples of forces? Select all that apply. a.a push b.friction c.a pull d.inertia

a,b,c

Which of the following are required to describe velocity? a.distance traveled, time of travel, and direction of travel b.distance traveled, direction of travel c.distance traveled, time of travel d.None of the above

a.

Which of the following represents Newton's Second Law of Motion? a.(Net force acting on an object) = (mass of the object)(acceleration of the object) b.(acceleration of an object) = (mass of the object)(net force acting on an object) c.(mass of the object) = (mass of the object)(acceleration of the object) d.(Net force acting on an object) = (acceleration of the object) / (mass of the object)

a.

Which of the following statements are TRUE regarding the "coin trick"? a.The NSTA card moves from a state of rest because a person exerts an unbalanced force on it b.There is a net force acting sideways on the coin, causing it to move with the card and NOT fall into the glass c.Both the NSTA card and coin remain at rest d.None of the above are true

a.

Which of the following would be examples of an object, once set in motion, remains in motion in a straight line forever without any external push to keep it moving. a.an asteroid moving through space (ignore the effects of the sun's gravity on the asteroid) b.Earth spinning on its axis c.the moon moving around the Earth d.time

a.

While a car travels north at a constant speed its a.acceleration is zero b.velocity is zero c.both of these are correct d.Neither of these are correct

a.

Why do we say velocity is a vector quantity and speed is not? a.Velocity describes magnitude and direction but speed describes only magnitude b.Speed describes both magnitude and direction but velocity describes only magnitude c.Velocity describes only magnitude

a.

Match the following with the appropriate units. a.Newtons b.meters/second for every second of time c.kilograms d.meters/second

a. force b. acceleration c.mass d.velocity

What are the two parts of Newton's First Law of Motion? Select all that apply. a.Objects at rest tend to remain at rest unless acted on by an unbalanced force b.Objects at rest tend to remain at rest unless acted on by a balanced force c.Objects in motion tend to stay in motion in a straight line unless acted on by an unbalanced force d.Objects in motion tend to stay in motion in a curved line unless acted on by an unbalanced force

a.&c.

A car moves with a forward thrust of 200 Newtons against a backward friction-drag of 100 Newtons. The car pulls a load of 20 kilograms. If you ignore the mass of the car and its driver, what is the net force on the car? a.0 Newtons b.100 Newtons c.5 meters/second d.5 meters/second for every second of travel

b

What is inertia? a.a force that a moving object carries with it b.a property of an object; an object's tendency to keep doing what it's doing c.a force that pushes back on a moving object d.a property of an object that depends on movement

b

Which of the following describes Newton's Second Law of Motion? a.The law explains that the natural tendency for things in the universe to stay at rest or in motion in a straight line b.The law explains the relationship between an object's mass, its acceleration, and the net force applied to the object c.The law explains how to every actions, there is an opposite and equal opposed reaction

b

You punch two objects as hard as you can, a piece of tissue paper and a concrete wall. Which punch hurts more? a.tissue paper b.concrete wall

b

If a camel can travel at an average velocity of 32km per hour, how far has it traveled after 3 hours? a.10 hr, approximately b.96 km c.96 km/hr d.There is not enough information given in the problem to determine the answer.

b use s=dt/t to solve

In this simulation from the Science Object, how does the man get off the ice? a.He uses a sled b.He throws snowballs to the side c.He crawls d.He walks

b.

In which of the following examples is the motion of the car accelerated? a.A car climbs a steep hill at the constant speed of 70 km/h. b.A car climbs a steep hill with its speed dropping from 18 km/h at the bottom to 9 km/h at the top. c.A car rolls backwards down a steep hill at a constant speed of 70 km/h. d.A car travels on a straight, flat road at the constant speed of 40 km/h.

b.

The speed of a car heading directly west changes from 45 miles/h to 75 miles per hour. In this example, a.Velocity is constant b.Velocity is changing c.Velocity is zero d.Acceleration is zero e.Acceleration is negative

b.

Using the following list, select all units that could be used to describe acceleration. a.m/s/s b.m/s2 c.s d.m e.m/s

b.

What part of Newton's First Law does Wiley the Coyote illustrate in the cartoon? a.Objects at rest tend to remain at rest b.Objects that are moving tend to keep moving c.To every action, there is an equal and opposed reaction d.Acceleration of an object is directly proportional to the net force exerted on the object

b.

You are driving from Sioux Falls to Rapid City on the interstate. Your vehicle is moving directly west at a constant speed of 75 miles per hour, and has a mass of 1500kg. The forward thrust force of your car's engine is 500 Newtons. You encounter a head-wind of 500 Newtons. Select the best statement. Draw a picture to help you understand what the problem is describing. a.No forces are acting on the car b.Net force on the car is zero c.There is an unbalanced net force acting on the car d.The car does not have any inertia

b.

A moving car has __________ inertia compared to the same car at rest. A hint: an elephant has the same amount of inertia whether it is standing still or charging at you. a.more b.less c.an equal amount of

c

Complete the following statement about Newton's first law of motion. An object at rest continues to stay at rest because it has: a.acceleration b.weight c.inertia d.speed

c

From the following list, select all units that could be associated with a vector quantity. a.kilogram (kg) b.milliliter (mL) c.meter/second (m/s)

c

How fast you are changing your speed, direction of travel, or both speed and direction of travel is a property of motion known as a.speed b.velocity c.acceleration d.None of these are correct

c

This time I push my kids in the stroller through mud. I continue to push my kids in the stroller with a force of 100 Newtons but encounter 25 Newtons of friction from the mud. The stroller and kids have an approximate mass of 50 kilograms. What is the resulting acceleration of the stroller? a.The stroller will not move b.The stroller will accelerate at 0.5 meters per second for every second of travel c.The stroller will accelerate at 1.5 meters per second for every second of travel d.The stroller will accelerate at 2.0 meters per second for every second of travel

c

What is needed to accurately describe the position of an object? a)distance to the object from a given point b)direction to the object from a given point c)both distance and direction to the object from a given point d)None of the above

c

i have four children; their ages are 10yo, 3yo, 2yo, and 5 months. To help transport all of these children when we leave the house, we have a double stroller. Which of the following scenario's will produce the greatest acceleration of the stroller if I push my kids with the same force? a.The 5 month old baby and the three year old are both in the stroller b.The two year old is in the stroller. He is built like a tank. c.The 5 month old baby is the only passenger d.The two and three year old are both in the stroller

c

While driving down the highway, a mosquito is squashed on your wind shied of your car. Think about carefully about Newton's 3rd Law. Select all that apply. he mosquito exerts a smaller force on your car than your car does on the mosquito a.Your car exerts a larger force on the mosquito than the mosquito exerts on the car; thus the bug is squashed b.The mosquito has more mass than the car; thus it is smashed by the car c.The force of the mosquito on the windshield is equal in magnitude to the force of the car on the mosquito d.The acceleration of the mosquito is greater than the acceleration of the car (if the car is accelerating at all) even though the same force is applied to both the mosquito and car

c&d

Complete the following statement: Newton's first law states that every object continues in a state of rest, or in a a state of motion in a straight line at a _________ speed, unless it is compelled to change that state by an unbalanced force. a.Increasing b.Decreasing c.Constant

c.

Galileo and Newton believed a.the natural state of objects was to be at rest on the Earth b.a continuous force was needed to keep objects moving c.a moving object would keep moving in a straight line forever if no outside forces acted on it d.Two of the above are correct e.All of the above are correct

c.

If an object falls with constant downward acceleration, the speed of the object must a.be constant also b.get smaller c.get bigger d.be zero

c.

In the picture, two tracks are shown. Notice that the ball's initial vertical height is always the same. Select the best answer. a.After the ball is dropped, it would rise higher in vertical height on Track A. b.After the ball is dropped, it would rise higher in vertical height on Track B. c.After the ball is dropped, it would rise to the same vertical height on both tracks. d.There is not enough information to answer given.

c.

Now let's consider the magnitude (or amount) of and direction of the force in the picture above. Let's say the man pushes on the wall with a force of 10 Newtons. Draw a picture to help you. Select the best answer. a.The wall does not push back on the man b.The wall pushes back on the man with a force that is less than 10 Newtons but opposite in direction c.The wall pushes back on the man with a force that is equal in magnitude to 10 Newtons but opposite in direction d.The wall pushes back on the man with a force that is greater in magnitude than 10 Newtons but opposite in direction

c.

Rub your hands together. This is an example of friction. What is friction? a.the tendency of an object to keep doing whatever it's doing b.the amount of matter within an object c.the force or resistance encountered when one body is moved in contact with another d.popcorn that turns fuchsia when popped

c.

Select the FALSE statement regarding net force. a.Net force is the sum total of all the forces acting on an object b.Two or more forces can cancel each other if they have opposing directions c.Direction of the forces is NOT important when determining net force d.A net force that is not equal to zero can also be described as an "unbalanced force"

c.

Select the best answer. a.In all of the scenario's, the box is at rest b.In all of the scenario's, no forces are exerted on the box c.In two of the scenario's, an unbalanced force acts on the box d.Two of the above are correct

c.

Which one of the following is a measure of inertia? a.Force b.Weight c.Mass d.Newtons

c.

With all other factors equal, if you double the mass of an object while a constant unbalanced force is applied, the acceleration will be . . . Hint: Or think about me trudging along in the mall with all 4 kids in tow, and my two year old Jack (who happens to weigh as much as his three year old brother Nolan) jumps in the stroller with Nolan. What will happen to acceleration? a.Doubled b.Increased fourfold c.decreased by one-half d.decreased by one-fourth

c.

If a car travels at an average speed of 60km/h for an hour, it will cover a distance of 60km. How far would it travel if it moved at this rate for 4h? a.15 km b.15 km/hr c.240 km d.240 km/hr

c. to solve 60km=dt/4hr.

Select the best answer. a.Mass is a measure of inertia. b.Weight is affected by gravity. c.The reluctance of an object to change its state of rest or of uniform motion in a straight line is called inertia. d.All of the above are true.

d

What factors are necessary to determine a vector quantity? a.magnitude and speed b.direction and speed c.direction and wind chill d.magnitude and direction

d

Do scientists believe there are situations in which Newton's laws do not apply? a.No, the laws apply all the time in all situations b.Yes, there are limits to Newton's laws c.At high speeds (near the speed of light), Newton's laws need some adjustment and do not apply d.Two of the above are correct

d both a&c

Does the speedometer on a vehicle show average speed or instantaneous speed? a.Both average and instantaneous speed are shown by a speedometer b.Neither average and instantaneous speed are shown by a speedometer c.Average speed d.Instantaneous speed

d.

In the Science Object, you watched an animation in which a tortoise won a race against a hare. Which one of the animals had a constant velocity? a.tortoise b.hare c.Both the tortoise and hare d.Neither the tortoise or hare

d.

In the simulation mentioned above, why was this method successful to get the man off the ice? a.The person was able to exert a backward force against the ice while walking b.The person was able to exert a backward force against the ice while crawling c.The person was able to exert a backward force against the ice while pushing a sled d.The person was able to exert a force against the snowball as it was thrown

d.

In which of the following examples is the motion of the car NOT accelerated? a.A car climbs a steep hill and goes over the crest and down on the other side, all at the same speed b.A car turns a corner at a constant speed c.A car climbs a steep hill and its speed decreases d.A car climbs a steep hill at a constant speed

d.

Newton's first law of motion describes a.force b.acceleration c.weight d.inertia

d.

Now thinking about Newton's Second Law . . . WHY did you select the scenario you selected in the above question? a.The scenario had the most mass b.The scenario had the most applied force c.The scenario had the most inertia d.The scenario had the least amount of inertia

d.

Using the following list, select all units that could be used to describe speed. a.m b.m/s2 c.s d.m/s e.m/s/s

d.

Which of the following describes Newton's Third Law of Motion? a.The law explains the conditions under which an object's motion will change b.The law explains that the natural tendency for things in the universe to stay at rest or in motion in a straight line. c.The law explains how forces affect changes in motion d.The law explains that whenever one object exerts a force on a second object, the second object exerts a force on the first object that is equal in magnitude and acts opposite in direction

d.

Which one of the following has the greatest amount of inertia? Hint: In this question, I want you to realize that the amount of inertia that an object has does not depend on its state of motion. In other words, a mack truck has the same amount of inertia whether it is at rest or moving down the highway at 75 mph. b.a bowling ball at rest c.a moving bowling ball d.an elephant e.a floating feather

d.

Why does the concrete wall hurt your fist more than the tissue paper? a.the tissue paper exerts less force on your hand than your hand exerts on the tissue paper b.the concrete wall exerts more force on your hand than your hand exerts on the wall c.the tissue paper has more inertia than the concrete wall d.the concrete wall has more inertia than the tissue paper

d.

Using Newton's Third Law of Motion, what is happening in the picture? a.The man pushes on the wall and the wall pushes back on the man b.When the man pushes on the wall, the electromagnetic forces among the atoms in the wall act like a spring and push back on the man c.The man pushes on the wall with a larger force than the wall pushes back on the man d.Two of the above are correct e.All of the above are correct

d. both a&b

Select the best answer. a.Velocity is an example of a vector quantity. b.The quantity of matter in an object (i.e., mass) is an example of a vector quantity. c.Speed is NOT an example of a vector quantity. d.Two of the above are correct. e.All of the above are correct

d. both a.&c.

Aristotle believed a.the natural state of objects was to be at rest on the Earth b.a continuous force was needed to keep objects moving c.a moving object would keep moving in a straight line forever if no outside forces acted on it d.Two of the above are correct e.All of the above are correct

d. two correct are a&b

hat are scientifically correct methods one can use to specify the position of an object? a.Longitude and latitude b.x and y coordinates on a grid c.distance from a given point to the object d.Two of the above are correct e.All of the above are correct

d. two are correct both a.&b.

In physics, what term describes a "push, pull, hit, or shove"?

force

Select the best answer. Use this figure to help you as you read the statements. applied force/net force diagram with boxes a.Net force is the sum total of all the forces acting on an object b.Direction of forces is important when determining net force c.If two forces act in the same direction, you add the forces together to determine net force d.If two forces act in opposite directions, you subtract the two forces to determine the net force e.Two of the above are correct f.Three of the above are correct g.All of the above are correct

g.

I push my kids in the stroller with a force of 100 Newtons on a frictionless surface like ice. The stroller and kids have an approximate mass of 50 kilograms. Assuming I can actually move on ice, what is the resulting acceleration of the stroller? a.0. 5 meters per second squared b.0.5 meter per second c.2 meters per second squared d.2 meters per second

use f=ma c