Learn more about force and motion in level 2 of Putter King's physics education series.

1. All materials copyright © 2011
Putter King LLC
All rights reserved
Unit #: 2011020202
Putter King LLC
Level 28 Shinagawa Intercity Tower A
2-15-1 Konan Minato-ku Tokyo, Japan
〒108-6028
Future KingsTM Education Program
Subject: Physics
Level 2 (Princess)
For the teacherʼs guide and all answers
please contact info@putterking.com

2. Physics
Level 2 - Princess
2

3. 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)
3
Summary

4. 4
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

5. 5
Gravity
Galileo 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.

6. 6
Law of Universal Gravitation
Fg =
m1 · m2
G
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

7. 7
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 kg
Putty WeightEarth: 70 kg * 9.81 m/s2 = 687 N
Putty WeightMoon: 70 kg * 1.63 m/s2 = 114 N

8. 8
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.

9. 9
Newtonʼs Second Law of Motion
Acceleration 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:

10. 10
Newtonʼs Third Law of Motion
For 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 = mg
Fg = (0.045 kg) * 9.81 m/s2
Fg = 0.44 N
n
n = 0.44 N
golf ball mass = 0.045 kg

11. 11
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

12. 12
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

13. 13
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