Newton's Second Law of Motion

​Newton's Second Law of Motion

By Kevin Goettge

Definitions:

You will need the following definitions to understand Newton's Second Law of Motion.

A push or pull measured in Newtons (N).

Force (F)

The amount of matter in an object; more mass = more inertia.

Mass (m)

A change in velocity (speed or direction) over time.

Acceleration (a)

Velocity is the speed of an object in a particular direction. It is a measure of both how fast something is moving and the direction it is heading

Velocity

The combination of all the forces acting on an object at the same time.

Example: During a game of tug-of-war, the left side pulls with a force of 300 N and the right side pulls with a force of 100 N. The Net Force is 200 N to the left.

Net Force (F_net)

F_net = 0 N

F_net = 200 N <---

Newton's Second Law of Motion

Acceleration of an object depends on the net force acting on it and the object’s mass.

​

The same force causes less acceleration for heavier objects and more acceleration for lighter ones.

Match

Match each term to its correct description.

• The amount of matter in an object

• Push or pull acting on an object

• Change in velocity over time

• Resistance of an object to any change in its state of motion

Mass

Force

Acceleration

Inertia

• Mass

• Force

• Acceleration

• Inertia

Multiple Choice

The equation that best describes Newton’s Second Law is:

• F=a/m

• F=m+a

• F=m-a

• F=m x a

Drag and Drop

Newton’s Second Law states that the acceleration of an object depends on the ​

Placeholder

applied to it and its ​

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.

Drag these tiles and drop them in the correct blank above

force

mass

acceleration

inertia

weight

velocity

Multiple Choice

The main engines of the space shuttle produce a strong upward thrust. According to Newton’s Second Law, what happens when thrust increases but the shuttle’s mass stays the same?

• Acceleration increases

• Acceleration decreases

• Force stays balanced

• Inertia disappears

Reorder

If the same thrust acts on three rockets, reorder based on who will accelerate the most:

1 = Most Acceleration

3 = Least Acceleration

• Mass. 549,054 kg

• Mass. 2,000,000 kg

• Mass. 2,800,000 kg

1

2

3

• 1
• 2
• 3

Multiple Choice

During launch, the shuttle’s engines produce 30 million newtons of thrust. This upward force must be unbalanced because:

• Gravity is stronger than thrust.

• The shuttle is not moving.

• The thrust is greater than gravity’s pull.

• Thrust and gravity are equal.

Multiple Choice

When the shuttle releases empty fuel tanks during flight, its acceleration increases. Why?

• Gravity becomes weaker at high altitudes.

• The shuttle’s mass decreases, so acceleration increases.

• The engines produce more thrust after separation.

• The shuttle gains more inertia.

Drag and Drop

When thrust and gravity are equal, the shuttle’s acceleration is ​

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.

Drag these tiles and drop them in the correct blank above

zero

maximum

infinite

negative

minimum

Reorder

Put the steps of a rocket launch in order to show how Newton’s Second Law applies:

• The shuttle engines fire and produce thrust.

• The net upward force exceeds the shuttle’s weight.

• The shuttle accelerates upward.

• The shuttle reaches constant speed when thrust balances drag and gravity.

1

2

3

4

• 1
• 2
• 3
• 4

Categorize

Options (6)

Firing an extra booster

Increasing engine thrust

Using lighter materials in design

Adding cargo to the shuttle

Filling extra fuel tanks

Doubling the payload weight

Drag the scenario into the correct category:

More Force → More Acceleration

More Mass → Less Acceleration

Multiple Choice

Astronauts test a small supply rocket and a heavy cargo rocket with identical engines. What can they conclude?

• The heavy rocket will accelerate faster.

• The small rocket will accelerate faster.

• Both accelerate the same.

• Acceleration depends only on friction.

Multiple Choice

If the shuttle’s engines suddenly shut off during ascent, which statement best describes its motion immediately after?

• It keeps accelerating upward.

• It stops instantly.

• It continues moving upward but slows down.

• It begins to accelerate faster upward.

Multiple Choice

Watch this video by Canadian astronaut Chris Hadfield.

When he squeezes water from the bag, the water floats in a ball instead of falling.
Which statement best explains why?

• Gravity is stronger in space.

• There is no unbalanced force pulling it down.

• The water has no mass in space.

• The water is magnetic.

Multiple Choice

Watch this video by Canadian astronaut Chris Hadfield.

Chris Hadfield explains that all of the astronauts share a tube of toothpaste. Why would they do that?

• To reduce the mass of the space shuttle.

• To promote teamwork among astronauts.
• To share germs and bacteria.
• To save money on supplies.

Multiple Choice

Watch this video by Canadian astronaut Chris Hadfield.

When he moves to his sleep pod, you see that he does not apply a lot of force, but he moves a far distance. Why is that?

• Because his mass is smaller in space, so he moves faster.

• Because gravity is pushing him forward toward his sleep pod.

• Because there are very few forces acting against his motion.

• Because the air in the space station helps push him forward.