Opening Activity: Ballistics Lab
Acceleration due to Gravity Variations Laboratory
Objective: Determining different ways to display data; build a graph that accurately displays the data.
Virtual Lab Starts here
Acceleration due to Gravity Variations Laboratory
Objective: Determining different ways to display data; build a graph that accurately displays the data.
- Using the cannon angle of 33 degrees, determine the velocity needed to hit the bulls-eye on each planet.
- On each planet, select a different (random) angle and determine the velocity RANGE necessary to hit the bulls-eye. (For example, on the planet Jupiter at 46 degrees, the velocity range needed to hit the target is 104 m/s to 114 m/s.)
Virtual Lab Starts here
Acceleration Due To Gravity
How Does Gravity Affect Falling Objects
Objective: Relate Newton's 2nd Law of Motion to the effect of gravity on falling objects.
Virtual Laboratory
How Does Gravity Affect Falling Objects
Objective: Relate Newton's 2nd Law of Motion to the effect of gravity on falling objects.
Virtual Laboratory
Bridge Building
Before beginning, answer the questions: 1 and 2.
1. What are the most common types of bridges? Describe each type.
2. List and define the basic forces that act on bridges. (Investigate Forces here) a. ________ b. ________ c. _________ d. ________ e. _________
3. The Romans are credited for this type of bridge shape: _____________________.
4. What kind of bridge is the strongest? Why?
5. What geometric shape(s) do engineers use to create the strongest bridges?
6.What are the steps to the Design Process?
7. Explain the advantages of a truss beam bridge compared to a solid beam bridge.
Create a table providing information on 5 bridges (only 1 can be from this area).
Your table should include charateristics of the bridges (height, how long, location, type, year built, any important history surrounding the bridge, etc.). BE COMPLETE (Bridge website).
Read about trusses.
What are three basic types of trusses? Include a labeled, rough sketch of each type.
Bridge Building Virtual Lab
A. Select the "Free download Bridge Builder (2000)" option to download the game.
B. Click the file at the bottom of the screen and select "RUN".
C. When prompted, in destination directory box enter c:/desktop/bridges. This is where the game will be. Good luck.
D. Create a table that records the amount spent and the amount leftover after each successful level.
A force is a push or pull upon an object resulting from the object's interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of the objects. When the interaction ceases, the two objects no longer experience the force. Forces only exist as a result of an interaction.
Contact versus Action-at-a-Distance Forces
For simplicity sake, all forces (interactions) between objects can be placed into two broad categories:
- contact forces, and
- forces resulting from action-at-a-distance
Contact forces are those types of forces that result when the two interacting objects are perceived to be physically contacting each other. Examples of contact forces include frictional forces, tensional forces, normal forces, air resistance forces, and applied forces.
Action-at-a-distance forces are those types of forces that result even when the two interacting objects are not in physical contact with each other, yet are able to exert a push or pull despite their physical separation. Examples of action-at-a-distance forces include gravitational forces. For example, the sun and planets exert a gravitational pull on each other despite their large spatial separation. Even when your feet leave the earth and you are no longer in physical contact with the earth, there is a gravitational pull between you and the Earth. Electric forces are action-at-a-distance forces. For example, the protons in the nucleus of an atom and the electrons outside the nucleus experience an electrical pull towards each other despite their small spatial separation. And magnetic forces are action-at-a-distance forces. For example, two magnets can exert a magnetic pull on each other even when separated by a distance of a few centimeters.
Examples of contact and action-at-distance forces are listed in the table below:
Contact Forces Action-at-a-Distance Forces
Frictional Force Gravitational Force
Tension Force Electrical Force
Normal Force Magnetic Force
Air Resistance Force
Applied Force
Spring Force
The Newton
Force is a quantity that is measured using the standard metric unit known as the Newton. A Newton is abbreviated by an "N." To say "10.0 N" means 10.0 Newton of force. One Newton is the amount of force required to give a 1-kg mass an acceleration of 1 m/s/s. Thus, the following unit equivalency can be stated:
1 Newton = 1 kg • m/s2
Force is a Vector Quantity
A force is a vector quantity. As learned in an earlier unit, a vector quantity is a quantity that has both magnitude and direction. To fully describe the force acting upon an object, you must describe both the magnitude (size or numerical value) and the direction. Thus, 10 Newton is not a full description of the force acting upon an object. In contrast, 10 Newton, downward is a complete description of the force acting upon an object; both the magnitude (10 Newton) and the direction (downward) are given.
Because a force is a vector that has a direction, it is common to represent forces using diagrams in which a force is represented by an arrow. Such vector diagrams were introduced in an earlier unit and are used throughout the study of physics. The size of the arrow is reflective of the magnitude of the force and the direction of the arrow reveals the direction that the force is acting. (Such diagrams are known as free-body diagrams and are discussed later in this lesson.) Furthermore, because forces are vectors, the effect of an individual force upon an object is often canceled by the effect of another force. For example, the effect of a 20-Newton upward force acting upon a book is canceled by the effect of a 20-Newton downward force acting upon the book. In such instances, it is said that the two individual forces balance each other; there would be no unbalanced force acting upon the book.
Other situations could be imagined in which two of the individual vector forces cancel each other ("balance"), yet a third individual force exists that is not balanced by another force. For example, imagine a book sliding across the rough surface of a table from left to right. The downward force of gravity and the upward force of the table supporting the book act in opposite directions and thus balance each other. However, the force of friction acts leftwards, and there is no rightward force to balance it. In this case, an unbalanced force acts upon the book to change its state of motion.
Force Problems (Final Practice)
- What is the unit of measure for force?
- What is the sum of all forces acting on an object called?
- Newton's First Law of Motion is also called __________________________________.
- Newton's first Law of Motion states that if there is no net force acting on an object it will_____________.
- Are mass and weight the same?
- If a net force of 7 N was constantly applied on 400 g object at rest, how long will it take to raise its velocity to 80 m/s?
- How much net force is required to accelerate a 5190 kg car at 4.43 m/s2?
- A 15.0 kg mass pulled along a frictionless surface by a horizontal force of 100 N will have what acceleration?
- A 49.5 kg parachutist lands moving straight downward with a speed of 3.85 m/s. If the parachutist comes to rest with constant acceleration over a distance of 0.630 m, what force does the ground exerts on her?
- If the gravity of Jupiter is 15 times greater than that of Earth, what is the mass of an object that has a weight of 8,512 N on the Jupiter?