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Putter King LLCLevel 28 Shinagawa Intercity Tower A 2-15-1 Konan Minato-ku Tokyo, Japan〒108-6028

Future KingsTM Education ProgramSubject: Physics

Level 2 (Princess)

For the teacherʼs guide and all answers please contact info@putterking.com

PhysicsLevel 2 - Princess

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Area of focus: force and motion

Topics covered:• Force• Gravity• Law of Universal Gravitation• Mass vs. weight • Newtonʼs First Law of Motion• Newtonʼs Second Law of Motion• Newtonʼs Third Law of Motion

Suggested time to complete (2 hrs):• Teaching material (40 minutes)• Practice activity (20 minutes)• Final project (60 minutes)

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Summary

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Force

A force is a push or a pull.

A force has both magnitude and direction, making it a vector quantity.

Scientists measure forces in units called newtons

• The newton (N) is the SI unit for force• 1 N = 1 kg·m/s2

F

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GravityGalileo discovered that freely falling bodies, heavy or light, have the same, constant acceleration and that this acceleration is due to gravity.

In other words, two objects of different weights falling from the same height will hit the ground at the same time. The acceleration of an object in free-fall is constant and independent of the mass of the object.

For example, without air resistance, a feather and a Putter King golf ball falling from the same height will hit the ground at the same time as both are equally affected by gravity.

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Law of Universal Gravitation

Fg =m1 · m2G

r2

G = universal gravitational constant G ≈ 6.674 x 10-11 N (m/kg)2

m1 = mass of object 1

m2 = mass of object 2

r = distance between the two objects

Newtonʼs law of universal gravitation states that every point mass in the universe attracts every other point mass with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

From this equation, we can derive the acceleration due to Earthʼs gravity on an object:

G = universal gravitational constant G ≈ 6.674 x 10-11 N (m/kg)2

Me = mass of Earth mEarth ≈ 5.9736 x 1024 kg

r = radius of Earth rEarth = 6.371 x 106 m

=G · Me

≈

r2

g 9.81 m/s2

g

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Mass vs. Weight

If you go to the moon, your weight will change but your mass will stay the same.

Weight is the force of gravity on an object.• Metric unit = newton (N)• US unit = pound (lb)

Mass is the quantity of matter in an object, or in other words, mass is the measure of the amount of "stuff" in something.• Metric unit = kilograms (kg)• Imperial unit = slug

Putty Mass: 70 kgPutty WeightEarth: 70 kg * 9.81 m/s2 = 687 NPutty WeightMoon: 70 kg * 1.63 m/s2 = 114 N

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An object at rest will remain at rest unless acted on by an unbalanced (outside) force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced (outside) force.

Newtonʼs First Law of Motion

Newtonʼs First Law of Motion was derived from Galileoʼs Law of Inertia. Isaac Newton developed the idea of Galileo further.

Newton concluded that an object will remain at rest or move with constant velocity when there is no net force acting on it. Net force is the sum of all forces acting on an object.

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Newtonʼs Second Law of MotionAcceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object).

F = ma

golf ball mass = 0.045 kg

golf ball acceleration = 5 m/s2

F = .225 N

In other words, force is equal to mass times acceleration:

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Newtonʼs Third Law of MotionFor every action, there is an equal and opposite reaction.

Gravity is acting downward.  The ball is at rest.  The ground must exert a force equal in magnitude and opposite in direction on the ball.  This force is called the normal force, n, since it is normal to the surface.

Fg = mgFg = (0.045 kg) * 9.81 m/s2

Fg = 0.44 N

nn = 0.44 N

golf ball mass = 0.045 kg

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Practice Activity

1) Calculate the normal force exerted by the ground

2) Calculate the weight of Bogey (the Putter Prince)

3) Calculate the net force on the golf club when the ball is struck

4) Calculate the net force on the golf ball when the ball is struck

(1)

(2)

(3)

(4)

Assumptions:• Golf ball mass = 45 g• Golf ball acceleration = 7 m/s2

• Bogeyʼs (the Putter Princeʼs) mass = 34 kg

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Requirements

Design and label a miniature golf hole (with a golfer) that includes at least:• 4 different forces• A demostration of each of Newtonʼs three laws of motion

For full points, be sure to:• Label the forces at work• Label and write a short explanation on the part of your diagram that demonstrates each of the three laws of motion• be creative!

Final Project

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Grading Rubric

Bogey(70% - 79%)

Par(80% - 89%)

Birdie(90% - 100%)

Forces• Student did not include four required forces• Student incorrectly calculated or labeled more than one force

• Student incorrectly calculated or labeled a force

• Student included at least four forces• Student correctly calculated and labeled all forces

Newtonʼs Three Laws of Motion

• Student diagram does not correctly demonstrate the laws of motion

or• Student did not include a demonstration of all three laws of motion

• Student diagram does not correctly or accurately demonstrate one of the laws of motion

• Student diagram correctly demonstrates the laws of motion• Student included a demonstration of all three laws of motion

Design• Miniature golf hole design is plain and simple• Student diagrams are sloppy or incorrectly labeled• Miniature golf hole design does not exhibit creativity

• Miniature golf hole design is playable • Student diagrams are neatly drawn and labeled

• Miniature golf hole design is playable and aesthetically pleasing• Student diagrams are neatly drawn and labeled• Miniature golf hole design is creative and original