Second Law

Newton's Second Law of Motion

By John Toje

Newton's 2nd Law of Motion

Law of Acceleration

We will investigate and analyze Newton’s second law of motion (law of force and acceleration).

I will calculate the acceleration of an object given its mass and the force used on it.

Newton's 2nd Law

The Law of Acceleration. Newton's second law of motion states that the acceleration of an object equals the net force acting on the object divided by the object's mass.

Acceleration and Mass

If the same force is applied to two objects:

As the mass increases the acceleration decreases.

Objects with more mass accelerate less.

Objects with less mass accelerate more.

Multiple Choice

If both rocks are pushed with the same amount of force, which rock would accelerate more?

• The 400kg Rock because it weighs more.

• The 40kg rock because it weighs less.

The 40kg rock will accelerate more because it weighs less. Remember the less mass, the more inertia.

Open Ended

Which object will accelerate more, the baseball or bowling ball? Explain your answer.

The baseball will accelerate more than the bowling ball because the baseball has more mass.

Multiple Choice

Which rock will accelerate the least?

• The Small Rock

• The Large Rock

The Large Rock accelerates the least because it has more mass than the small rock.

Multiple Choice

Which grocery basket will have the least acceleration, if both grocery baskets are pushed with the same amount of force?

• The one without groceries because it has more mass.

• The one with groceries because it has more mass.

• The one without groceries because it has the least mass.

• The one with groceries because it has least mass.

Multiple Choice

Both objects are pushed with the same amount of force, which object will accelerate more the car or the basket ball?

• The basketball will accelerate the the most because it has the less mass than the car.

• The basketball will accelerate the least because it has the more mass than the car.

• The car will accelerate the the most because it has the less mass than the car.

• The car will accelerate the least because it has the more mass than the basketball.

Multiple Choice

The larger the mass you have the _____ force you need to change its motion.

• more
• less

Multiple Choice

A force of 90N is applied to each cart below, which one will accelerate the fastest?

• Cart 1

• Cart 2

• Cart 3

• Cart 4

Acceleration and Force

As the force increases the acceleration increases.

Objects with less force accelerate less.

Objects with more force accelerate more.

Multiple Choice

The child applies a force of 5N when she pushes the swing. Her dad applies a force of 25N when he pushes the swing. Which swing will accelerate more2

• The swing the Dad pushes.

• The swing the child pushes.

The swing the dad pushes will accelerate more because the dad applies a greater force to the swing.

Multiple Choice

Johnny throws a baseball with 75 N of force. Roger throws a baseball with 200 N of force. Which person's baseball will accelerate the least?

• Johnny's Baseball

• Roger's Baseball

Johnny's baseball will accelerate the least because Johnny used 75N of force. Johnny used less force than Roger.

Multiple Choice

Joshua and Elijah are playing cars. Joshua pushed his car with 12N of force towards the finish line. Elijah pushed his car with 20N of force towards the finish line. Who's car made it to the finish line first?

• Joshua's car made it to the finish line first because he applied more force so it accelerated more.

• Joshua's car made it to the finish line first because he applied less force so it accelerated more.

• Elijah's car made it to the finish line first because he applied more force so it accelerated more.

• Elijah's car made it to the finish line first because he applied more less so it accelerated more.

Multiple Choice

A greater applied force is required to move an object with a greater mass than one with a smaller mass.

• True
• False

Newton's 2nd Law of Motion

• Law of Acceleration

• There is an equation.

• F=MA

• Study the Triangle

Multiple Choice

Using the triangle. What is the formula for force?

• Force = Mass x Acceleration

• $$Accleration=Force\ \div\ Mass$$

• $$Mass=Force\ \div Accleration\$$

Force = 

Mass x Acceleration 

Multiple Choice

Using the triangle. What is the formula for Acceleration?

• Force = Mass x Acceleration

• $$Accleration=Force\ \div\ Mass$$

• $$Mass=Force\ \div Accleration\$$

Acceleration= 

Force / Mass

Multiple Choice

Using the triangle. What is the formula for Mass?

• Force = Mass x Acceleration

• $$Accleration=Force\ \div\ Mass$$

• $$Mass=Force\ \div Accleration\$$

Mass= 

Force / Acceleration

To Find Force

• Multiply the Mass and the Acceleration

• Mass=kg

• Acceleration=m/s2

Let's Practice Finding Force

• An object with a mass of 2.0 kg accelerates 2.0 m/s2 when an unknown force is applied to it. What is the amount of the force? 

Multiple Choice

An object with a mass of 2.0 kg accelerates 2.0 m/s2 when an unknown force is applied to it. What is the amount of the force?

What is the question asking you tp solve?

• force

• mass

• acceleration

The question is asking you to find the force. I underlined it so you would know.

• An object with a mass of 2.0 kg accelerates 2.0 m/s2 when an unknown force is applied to it. What is the amount of the force? 

Multiple Select

According to the formula(f=mxa), and the triangle. What 2 variables are needed to calculate the force?

• Mass

• Acceleration

• Force

You need to determine the mass and acceleration in the question.

I highlighted the Mass and Acceleration below. An object with a mass of 2.0 kg accelerates 2.0 m/s2 when an unknown force

is applied to it. What is the amount of the force? 

Multiple Choice

An object with a mass of 2.0 kg accelerates 2.0 m/s2 when an unknown force is applied to it. What is the amount of the force?

• 2.0kg

• 2.0m/s2

• 4N

• 20N

The answer is 4N.

• F=MA

• M=2kg

• A=2.0m/s2

• F=2kgx2m/s2

Multiple Choice

A 25 kg bike accelerates at 10 m/s². What was the force?

• 250 N

• 2.5 N

• 25 N

• 15 N

To Find Acceleration

• Divide the Force and the Mass

• Mass=kg

• Force =N

Let's Practice Finding Acceleration

• An object with a mass of 5.0 kg has a force of 20.0 newtons applied to it. What is the resulting acceleration of the object?

Multiple Choice

An object with a mass of 5.0 kg has a force of 20.0 newtons applied to it. What is the resulting acceleration of the object?

What is this question asking you to solve for?

• Mass

• Acceleration

• Speed

• Force

The question is asking you to find the ACCERLERATION. I underlined it so you would know.

• An object with a mass of 5.0 kg has a force of 20.0 newtons applied to it. What is the resulting acceleration of the object?

Multiple Select

According to the formula(f=mxa), and the triangle. What 2 variables are needed to calculate the acceleration?

Remember Acceleration = Force/Mass

• Mass

• Acceleration

• Force

You need to determine the mass and acceleration in the question.

I underlined the Force and Mass below. An object with a mass of 5.0 kg has a force of 20.0 newtons applied to it. What is the resulting acceleration of the object?

Multiple Choice

An object with a mass of 5.0 kg has a force of 20.0 newtons applied to it. What is the resulting acceleration of the object?(Remember to divide the force and the mass.)

• 5kg

• 20 N

• 100 m/s2

• 4 m/s2

The Answer is 4 m/s2.

Multiple Choice

If a 2kg bird is pushed by the wind with a force of 2N, how fast does the bird accelerate?

• 1 m
• 2 m/s²
• 4m/s²
• 1 m/s²

To Find Mass

• Divide the Force and the Acceleration

• Force =N

• Acceleration=m/s2

Let's Practice Finding Mass

• An object accelerates 12.0 m/s2 when a force of 6.0 newtons is applied to it. What is the mass of the object?

Multiple Choice

An object accelerates 12.0 m/s2 when a force of 6.0 newtons is applied to it. What is the mass of the object?

What is this question asking you to solve for?

• Mass

• Acceleration

• Speed

• Force

The question is asking you to find the Mass. I underlined it so you would know.

• An object accelerates 12.0 m/s2 when a force of 6.0 newtons is applied to it. What is the mass of the object?

Multiple Select

According to the formula(f=mxa), and the triangle. What 2 variables are needed to calculate the mass?

Remember Mass=Force/Acceleration

• Mass

• Acceleration

• Force

• Speed

You need to determine the FORCE and ACCELERATION in the question.

I highlighted the Force and Acceleration below. An object accelerates 12.0 m/s2 when a force of 6.0 newtons is applied to it. What is the mass of the object?

Multiple Choice

An object accelerates 12.0 m/s2 when a force of 6.0 newtons is applied to it. What is the mass of the object?

• 2 kg

• 0.5kg

• 6 kg

• 24 kg

The Answer is 0.5 kg.

• undefined

• F = 6N

• A = 12.0 m/s 2 

• Mass = 6N / 12.0m/s2

• Mass = 0.5KG

Multiple Choice

If an object was accelerating at 5 m/s², and a force of 10 newtons was required to accelerate it, what was the object's mass?

• 50 kg

• 2 kg

• 0.5 kg

• 5 kg

Multiple Choice

You give a shopping cart a shove down the isle. The cart is full of groceries and has a mass of 18 kg. The cart accelerates at a rate of 3 m/s². How much force did you exert on the cart?

• 6N
• 54N
• 21N
• 18N

Multiple Choice

Determine the accelerations that result when a 12-N net force is applied to a 3-kg object and then to a 6-kg object.

• A 3-kg object experiences an acceleration of 2 m/s/s. A 6-kg object experiences an acceleration of 2m/s/s.  
• A 3-kg object experiences an acceleration of 4 m/s/s. A 6-kg object experiences an acceleration of 2 m/s/s.  
• A 3-kg object experiences an acceleration of 2 m/s/s. A 6-kg object experiences an acceleration of 4 m/s/s.  
• A 3-kg object experiences an acceleration of 4 m/s/s. A 6-kg object experiences an acceleration of 4 m/s/s.  

Multiple Choice

The classes are playing tug of war. Barsoum’s room pulls to the left with a force of 45 N. Coach Camacho's room pulls to the right with a force of 50 N. What is the net force? And who won?

• 5N right. Coach Comacho's Class won.
• 5N Left. Barson's class won. 
• 95N and Coach Comacho's class won. 
• 95N and Barson's class won.

Multiple Choice

A force of 250 N is applied to an object that accelerates at a rate of 5 m/sec².  What is the mass of the object?

• 100kg 
• 1,250kg
• 50kg
• 5kg

Multiple Choice

A 50 kg skater pushed by a friend accelerates 5 m/sec².  How much force did the friend apply?

• 45 N
• 15 N 
• 10 N
• 250 N

Multiple Choice

What is the acceleration of a 50 kg object pushed with a force of 500 newtons?

• 100 m/s²
• 25,000 m/s²
• 10 m/s²
• 25 m/s²

Multiple Choice

How much force is needed to accelerate a 25kg bowling ball at 2m/s². 

• 50N
• 5N
• 12.5N
• 100N

Multiple Choice

How much force is needed to accelerate a 3kg skateboard at 5m/s^2. 

• 8N
• 1.6N
• 0.6N
• 15N