# 2015-02-12 Freshman Science Physics Activity 2

## We discuss Newton's Second Law and how to interpret in words and symbols (numbers).

Physical SciencePhysics

# 2015-02-12 Freshman Science Physics Activity 2

Created 3 years ago

Duration 0:24:21
116
We discuss Newton's Second Law and how to interpret in words and symbols (numbers).
Slide Content
1. ### Slide 1 - Coordinated ScienceChapter 1 Activity 2

• Mr. Weisenfeld
2. ### Slide 3 - Date: Thu., Feb. 12, 2015

• Objective: Our goal today is to get comfortable using Newton’s 2nd Law (N2L).
• We will know we have learned this when we can use (force = mass times acceleration) correctly with both words and numbers.

4. ### Slide 5 - Entry Task: Choose one of the following statements in your notebook, write it out and complete it based on your experiences in the lab:

• “The greater the constant, unbalanced force pulling on an object, _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.”
• “When equal amounts of constant, unbalanced force are used to pull objects having different masses, the more massive object, _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.”

7. ### Slide 9 - Let’s look at the definition in pieces.

• “The acceleration of an object”
• Means an object is speeding up
• The units are meters per second per second
• If Speed is meters per second (like miles per hour, or feet per second)
• Then Acceleration is (meters per second) per second
• An object that is getting faster has more (meters per second) every second.
8. ### Slide 11 - In the following simulation

• Click on Acceleration to get started
• 2. Check to show speed and acceleration of the box.
• 3. Click on the black arrows to apply a force to the box.
9. ### Slide 13 - You should have seen (go back if you have to):

• Unless the force applied is greater than friction, the box won’t move.
• If the force is greater than friction, the box will have an acceleration.
• If the box has an acceleration, then the speed is increasing.
• If you stop pushing, the box will slow down and stop due to friction.
• If you start pushing against the motion, it will slow down quicker.
• If you turn off friction, a small force will get the box moving, faster and faster and faster…
• If you give a small push and then stop, the box will move at a constant velocity when there is no friction.
10. ### Slide 14 - Next piece of the definition.

• “The acceleration of an object is directly proportional to the unbalanced force acting on it”
• Means that if you don’t have an unbalanced (or net) force, nothing is going to move.
• Means that the harder you push the greater the acceleration.
• * Go back to the simulation and try it right now if you don’t believe me…
11. ### Slide 16 - Next piece of the definition.

• “The acceleration of an object is directly proportional to the unbalanced force acting on it and inversely proportional to the objects mass.”
• Now keep the force constant and change the mass.
• Inversely proportional means that if you double the mass the acceleration goes down by 1/2, for the same force.
• * Go back to the simulation and try pushing on two boxes, instead of just one…
12. ### Slide 18 - The last piece of the definition.

• “…The direction of the acceleration is the same as the direction of the unbalanced force.”
• In pictures, this box has a net force (greater force, unbalanced force) to the right, and so it is accelerating to the right.
13. ### Slide 20 - That was N2L in words now how about symbols?

• If you are given any two of , , or , you can find the third.