Select your language

Suggested languages for you:
Log In Start studying!
StudySmarter - The all-in-one study app.
4.8 • +11k Ratings
More than 3 Million Downloads
Free
|
|

All-in-one learning app

  • Flashcards
  • NotesNotes
  • ExplanationsExplanations
  • Study Planner
  • Textbook solutions
Start studying

Physics of Motion

Save Save
Print Print
Edit Edit
Sign up to use all features for free. Sign up now

Want to get better grades?

Nope, I’m not ready yet

Get free, full access to:

  • Flashcards
  • Notes
  • Explanations
  • Study Planner
  • Textbook solutions
Physics of Motion

How and why do things move the way that they do? Be it a ball thrown in the air, or a train traveling across a track, everything follows specific rules when they're in motion. In physics, motion is described as a change in the position of an object throughout a period of time. Motion is capable of being both complex or simple, completely depending on what is being moved, and the environment it is in. The motion of an object is entirely affected by the forces acting on it at any given time, as well as forces that have acted on it in the recent past. For example, if I were to throw a ball and it was currently in mid-air, the push I gave that ball has already happened, but the effects of that force are still going to carry on until the motion of that ball has stopped.

Motion is completely dependent on the things around it, meaning it is relative. The fact that an object is moving or stationary is only true if everything around the object is also stationary to the person observing the stationary object. For example, a flag may be stationary on the Moon from the eyes of an astronaut, but the Moon is also orbiting the Earth, which in turn is orbiting the Sun, etc.

In physics, motion can be defined and calculated using a few variables that all bodies in motion have or can have: velocity, acceleration, displacement, and time. Velocity is the same as speed but depends on the direction a body is traveling, and the same can be said for displacement in terms of distance. Acceleration is the same as velocity but describes how much of a change in speed occurs over some time, instead of how much of a change in distance.

Physics of Motion parabolic motion StudySmarterAn example of a parabolic curve of a ball in motion, StudySmarter Originals

Gravity is a force that causes acceleration!

What Formulas Do We Use When Calculating Motion?

When it comes to solving for any of these variables, we have five main equations that we can use:

The first is given as

This is the most simple formula, meaning that distance is equal to speed multiplied by time, only taking into account direction as well. This can only be used when acceleration is equal to 0.

The second equation is one of the three kinematic equations. Note that it does not depend on position.

Whereis the final velocity of an object,is its starting velocity,is the acceleration acting on it, andis the time that passes during motion.

Our third equation is another kinematic equation. This time it does not depend on the final velocity.

Where is the displacement. This formula can only be used if the acceleration on the object is positive.

Our fourth equation below is an easier way to calculate displacement when you know both the starting and final velocities that act on the object.

And our last equation is also the final kinematic equation. Note it does not depend on time :

Using these equations, we can solve for any particular variable we need to when studying an object in motion.

Since acceleration is a rate of change in velocity, We can find the average acceleration by taking the difference between our final velocity,and initial velocity,and dividing that over our time interval,In other words,

Where the bar abovesignifies average.

What Are the Laws of Motion?

The laws defining the behavior of motion were first discovered and written by English physicist Sir Isaac Newton, and they apply to almost everything in the universe.

Some things do not follow these laws, such as objects traveling at close to the speed of light which follow Einstein's theory of relativity, and things smaller than atoms, which follow behaviors defined in the field of quantum mechanics.

First Law: Law of Intertia

In simple terms, the first law of motion states that objects that are not being pushed will eventually come to rest. This means that if an object is experiencing no change in the forces acting on it, the object will tend towards a state of no movement, or rest.

This law was first discovered as a way to explain why don’t feel all the movement that goes on in the universe. We are standing on a planet that is spinning and moving around a sun that is moving around a galaxy, why can’t we feel all that movement? Well, since we are moving with the Earth as we are standing on it, we keep that motion constantly, and from our perspective, we are at rest.

Second Law: F = ma

The second law of motion shows us that rate of change of the momentum of an object is exactly the same as the force that is being applied to it. In other words, if an object has a mass ofthe force acting on it is equal to its mass multiplied by its acceleration. This can be written as

Third Law: Action & Reaction

The main way this law has been stated in the past is that every action has an equal and opposite reaction. This isn’t quite true, or just not quite informative enough. The third law of motion states that when two objects are to come into contact with each other, the forces that are applied to one another are equal in magnitude and opposite in direction.

For example, if an object is laying on the ground, the object is pushing down on the ground with its weight, which we know is a force. As we know of the third law of motion, we know that the ground is also pushing back, with a force equal to the weight and in the exact opposite direction.

What Are the Types of Motion?

Movement occurs in a multitude of different ways, and the forces that are applied to objects in these different states of movement vary greatly. Here are a few types of motion:

Linear Motion

Linear motion is straightforward, as it describes any form of movement that occurs in a straight line. This is the most basic form of motion. Nothing special or complicated has to occur when traveling from point A to point B.

Oscillating Motion

Oscillating motion is a back and forth movement. Only when this movement is consistent over time can it be considered an oscillating motion. Waves, including sound waves, ocean waves, and radio waves are examples of oscillating motion. Waves use oscillating motion to store information in their amplitudes. Other common examples of oscillating motion are pendulums and springs.

Physics of Motion oscillating motion StudySmarterA spring is a great example of an oscillating motion, Wikimedia Commons

Rotary Motion

Rotary motion will move in a circular pattern. The use of this motion has been incredibly beneficial to use over time, with the use of the wheel to transport things, as well as many other real-world examples.

A diagram of rotary motion, showing the direction of velocity and acceleration. Brews ohare CC BY-SA 3.0

Projectile Motion

Projectile motion is the movement of any object when thrown in an environment containing a gravitational field. If an object is thrown higher than horizontally, then the path it travels will form a curve, known as a parabola.

There is another lesser-known form of motion, irregular motion. This is a form of movement that doesn’t adhere to any fixed pattern, as the other forms of motion do.

Physics of Motion - Key takeaways

    • Motion in physics is a change in the position of an object or body over a time interval.

    • Motion is relative, meaning that whether something is in motion or not depends on the state of motion of the bodies it is surrounded by.

    • There are many formulas used to calculate variables that are relevant in motion, such as displacement, time, velocity, and acceleration.

    • There are three laws of motion, the law of inertia, the law of F=ma, and the law of action & reaction.

    • There are a few different types of motion, including linear, oscillating, and rotary motion.

Frequently Asked Questions about Physics of Motion

Motion in physics can be described as a change in the position of a body over a period of time.

The 3 laws of motion are the law of inertia, the law of F=ma, and the law of action & reaction.

The different types of motion in physics are linear motion, oscillating motion, rotary motion, and irregular motion.

Final Physics of Motion Quiz

Question

What are the forces applied on a book that is at rest on the table? 

Show answer

Answer

  1. The weight W exerted by the earth on the book 
  2. The normal force N exerted by the table on the book

Show question

Question

What are the forces applied on a block suspended by a rope? 


Show answer

Answer

  1.  The weight W exerted by the earth on the block.
  2. The tension force T exerted by the rope on the block.

Show question

Question

What are the forces applied on a block that is placed on a table and being pushed by a force Fa horizontally to the right? 


Show answer

Answer

  1. The weight W exerted by the earth on the block. 
  2. The normal force N exerted by the table on the block.

  3. The acting force Fa that is pulling the block horizontally to the right. 

  4. The force of friction exerted by the table on the block in the opposite direction of motion (horizontally to the left).

Show question

Question

Each item in the issue requires a distinct free-body diagram.

 

Is this statement true or false? 


Show answer

Answer

True. 

Show question

Question

A free-body diagram is a valuable tool for evaluating all of the forces that operate on a body and studying its motion. 

Is this statement true or false? 

Show answer

Answer

True.

Show question

Question

At each point of contact, there is always one applied force on the object in question.

 

Is this statement true or false? 

Show answer

Answer

False. 

At each point of contact, there is at least one force; there may be more. 

Show question

Question

The normal force acting on a body is always perpendicular but it can be upward or downward. 

 

Is this statement true or false?

Show answer

Answer

False. 

The normal force is always perpendicular to the surface and directed upward.

Show question

Question

In a free body diagram, the direction of acceleration is the opposite of the direction of the net force.


Is this statement true or false? 


Show answer

Answer

False. 

In a free body diagram, the direction of acceleration is the same as the direction of the net force.

Show question

Question

The net force in a free body diagram can be zero. 

 

Is this statement true or false? 

Show answer

Answer

True. 

Show question

Question

If the net force applied on a system is zero, then the object is not acceleration. 

 

Is this statement true or false? 

Show answer

Answer

True. 

Show question

Question

If the component of the net force along the x-axis was positive: 

Then the skier will be accelerating downward to the left. 

 

Is this statement true or false?  

Show answer

Answer

False. 

The skier will be accelerating downward to the right. 

Show question

Question

 

Each vector force has two components, one along the x-axis and one along the y-axis. 

 

Is this statement true or false? 

Show answer

Answer

True. 

Show question

Question

Speed is a scalar number that describes "the rate at which an item moves." 


Is this statement true or false? 

Show answer

Answer

True.

Show question

Question


Is this statement true or false? 

Show answer

Answer

False. 

Show question

Question

Physicists utilize the basic concepts of speed and velocity to describe the motion of objects in terms of : 

Distance and Time. 


Is this statement true or false? 

Show answer

Answer

False. 

Physicists utilize the basic concepts of speed and velocity to describe the motion of objects in terms of : 

Distance, Time and Direction. 

Show question

Question

There is no difference between speed and velocity. 


Is this statement true or false? 

Show answer

Answer

False. 

The two parameters differ. 

Show question

Question

While velocity is a scalar value, speed is a vector. 


Is this statement true or false?


Show answer

Answer

False. 

While speed is a scalar value, velocity is a vector.  

Show question

Question


Is this statement true or false? 

Show answer

Answer

True. 

Show question

Question

We need to differentiate between the speed and average speed of an object since its speed may vary with time. 


Is this statement true or false? 

Show answer

Answer

True 

Show question

Question

The mean value of a body's speed over a period of time is called instantaneous speed. 


Is this statement true or false?



Show answer

Answer

False. 

The mean value of a body's speed over a period of time is called the "average speed."

Show question

Question

To calculate the average speed, we divide the total distance traveled over the total time needed. 


Is this statement true or false?


Show answer

Answer

True. 

Show question

Question

The speed can be measured or expressed in: 

kilometers per second (m/s),


Is this statement true or false?

Show answer

Answer

False. 

The speed can be measured or expressed in: 

  • meters per second (m/s), where the distance will be expressed in meters and time in seconds. 

  • kilometers per hour (km/h), where the distance is measured in kilometers and the time in hours.

Show question

Question

The average can only be calculated if the speed of the moving object is varied with time. 


Is this statement true or false? 

Show answer

Answer

True. 

Show question

Question

Even if the particles may have different translational acceleration, they have the same angular acceleration. (True/False)


Show answer

Answer

True


Show question

Question

How to calculate the moment of inertia of a thin cylindrical shell?


Show answer

Answer

I=MR2

Show question

Question

Suppose a car moving at 70 mph drives past you. Will its maximal angular velocity with respect to you be bigger or smaller if it passes closer-by?

Show answer

Answer

Bigger.

Show question

Question

Is the angular velocity of something moving directly away from you zero or non-zero?

Show answer

Answer

Zero.

Show question

Question

Is the angular velocity of something moving in a straight line that doesn't touch you zero or nonzero?

Show answer

Answer

Nonzero.

Show question

Question

You are standing on a runway and a flying plane and a squirrel are both moving directly toward you. The angular velocity of which object is larger?

Show answer

Answer

Their angular velocities are equal.

Show question

Question

Which of the following two objects will have a larger angular velocity with respect to your eyes? An ant walking full speed over your arm or a car driving full speed over a highway 10 km away?

Show answer

Answer

The ant.

Show question

Question

The first scientist known to have put forward ideas about falling objects was Galileo.

Show answer

Answer

False.

Show question

Question

According to Aristotle, heavy objects fall before light objects.

Show answer

Answer

True.

Show question

Question

What was Galileo's experiment and what did he prove?

Show answer

Answer

Galileo performed an experiment that showed that two objects of different weights dropped at the same time from the Leaning Tower of Pisa fell to the ground almost simultaneously. 

Show question

Question

What is free fall?

Show answer

Answer

In an environment where air resistance is neglected, the objects left without speed move only under the effect of gravitational force. This motion is called free fall.  

Show question

Question

Neglecting air resistance, if a stone and a paper cup are released from the same height at the same time, they will accelerate with equal gravitational acceleration and fall to the ground at the same time.


Show answer

Answer

True.

Show question

Question

What experiment did astronaut David Scott perform?

Show answer

Answer

On August 2, 1971, astronaut David Scott conducted a free-fall experiment on the Moon, dropping a hammer and a feather simultaneously. As predicted, they hit the lunar surface at the same time.

Show question

Question

The acceleration of falling objects in an environment where air resistance is neglected is always the acceleration of gravity and does not depend on the mass of the object. 


Show answer

Answer

True 

Show question

Question

What happens when an object undergoes free fall?

Show answer

Answer

When an object undergoes free fall, it starts with zero initial velocity and keeps on increasing its velocity at a rate of 9.8 m/s, hence, it experiences an acceleration of 9.8 m/sec2 which is also known as acceleration due to gravity. 

Show question

Question

What is the final velocity of the ball if it is dropped from a certain height and takes 10 seconds to reach the ground? The air resistance is not taken into account.  (g= 10 m/s2)

Show answer

Answer

100 m/s

Show question

Question

Kevin dropped his ball from a height of 5 meters and then he ran downstairs really fast to see if he can catch the ball, he takes 1 minute to reach the ground. Will he be able to catch the ball? Please note that the air friction is neglected.


Show answer

Answer

No

Show question

Question

If an object undergoes Free fall, what will be the velocity of the object on the 10th second? (g=10 m/s2)


Show answer

Answer

-100 m/s

Show question

Question

Find the height from which a toy is dropped, if it goes in free fall state and the final velocity achieved by the toy is 10 m/s. (g=10 m/s2)


Show answer

Answer

5 m

Show question

Question

Find the height from which a toy is dropped, if it goes in free fall state and the final velocity achieved by the toy is 30 m/s. (g=10 m/s2)


Show answer

Answer

45 m

Show question

Question

If an object undergoes Free fall, what will be the velocity of the object on the 5th second? (g=10 m/s2

Show answer

Answer

-50 m/s

Show question

Question

What is the final velocity of the ball if it is dropped from a certain height and takes 5 seconds to reach the ground? The air resistance is not taken into account.  (g= 10 m/s2

Show answer

Answer

-50 m/s

Show question

Question

Describe what mass is in basic terms.

Show answer

Answer

Mass is how much of something there is, or how much matter makes up something.

Show question

Question

Does everything have mass?

Show answer

Answer

No, almost everything has mass, but things such as photons, which are light particles do not have mass.

Show question

Question

What is the official unit of mass according to the International System of Units?


Show answer

Answer

Kilograms.

Show question

Question

What is the difference between mass and weight?


Show answer

Answer

Mass is how much matter something is made up of, whereas weight is used to describe both the mass and the gravitational pull acting on a mass.

Show question

Question

Would you weigh more or less on the Moon?


Show answer

Answer

You would weigh less on the Moon

Show question

60%

of the users don't pass the Physics of Motion quiz! Will you pass the quiz?

Start Quiz

Discover the right content for your subjects

No need to cheat if you have everything you need to succeed! Packed into one app!

Study Plan

Be perfectly prepared on time with an individual plan.

Quizzes

Test your knowledge with gamified quizzes.

Flashcards

Create and find flashcards in record time.

Notes

Create beautiful notes faster than ever before.

Study Sets

Have all your study materials in one place.

Documents

Upload unlimited documents and save them online.

Study Analytics

Identify your study strength and weaknesses.

Weekly Goals

Set individual study goals and earn points reaching them.

Smart Reminders

Stop procrastinating with our study reminders.

Rewards

Earn points, unlock badges and level up while studying.

Magic Marker

Create flashcards in notes completely automatically.

Smart Formatting

Create the most beautiful study materials using our templates.

Just Signed up?

Yes
No, I'll do it now

Sign up to highlight and take notes. It’s 100% free.