Weight in Relation to Mass

Our group did the activity with newtons vs. grams.  We noticed a pattern that for about every 100 g of mass, there was 1 N of weight.  The data represented in a graph created a direct linear relationship:


Image via: http://www.arborsci.com/cool/the-importance-of-the-best-fit-line

This shows that their relationship is 10N/Kg.

In class, we found the equation for newtons was N= Kg*m/s^2

Overall:
100g=1N
1Kg=10N

More Force Stuff

Last class, we cleared up more facts about forces and made this list:

We all agreed that on a force diagram if the forces are equal, they should appear equal and have congruency markings.  Those forces with unequal magnitude should appear unequal in length and not have congruency markings.  We also decided that the force diagrams will only show forces acting upon an object at one specific time, even if the object is already in motion caused by a different force.  Another thing the class decided was that all the arrows should come from the "dot" or object that the forces are acting upon.  As for initial velocity for an object that was already in motion, I think we should still include a side note of it because it is useful information for if we were doing a lab and made force diagrams for different situations.  I understand overall how to draw a basic motion map now.

Force Diagrams

Last class, we came to a consensus that in force diagrams, there are equal forces with an object pushing on the earth and the earth pushing back that result in the object staying at rest, or have a velocity of 0.  In a force diagram where the object is moving from rest, it's the same diagram as one at rest but with another force exerted by another object, such as the mallet from the bowling ball activity.  But there's one thing everyone couldn't seem to agree on: how a force diagram would look if the object was not starting at rest (already moving).  Would there be another arrow on the diagram to show it?  Would it just not be included?  The idea that made the most sense to me was to add a note stating the initial velocity to show that it would increase after being affected by whatever force was being exerted upon in the diagram because the initial velocity is useful/ necessary information, especially if you're creating graphs or motion maps from this data.

Position vs Time, Velocity vs Time, and Acceleration vs Time Graphs Review

When an object is rolling down a ramp, the graphs of this action should look like the following:

 

(replace the word displacement with position), image via http://www.thefullwiki.org/FHSST_Physics/Rectilinear_Motion/Graphs

As you can see, the position gradually increases more and more per second, meaning the velocity increases constantly and the object is constantly acceleration.  We also discovered in class that the slope of the position is the velocity and that the slope of the velocity is the acceleration, which explains why the graphs go from being a curve to linear to a straight line.

This means when the position increases at a constant rate, the velocity has a slope of zero (straight line across) and there is no acceleration, as shown below: 

image via http://www.bbc.co.uk/bitesize/higher/physics/mech_matt/analyse_motion/revision/1/

Ramp Car Lab vs. Flat Surface Car Lab

Our class has done 2 car labs in the past few classes.  In the one on a flat surface, the car had a constant speed, velocity, and acceleration.  In the one on a ramp, the velocity, speed, and acceleration all increased more as it went on.  Both have a constant starting position.  The difference between the position graphs was that the one across a flat surface had a linear function since the slope (m/s) was constant.  The ramp car's slopes gradually increased more and more so it resulted in a quadratic function.  What exactly are the slopes in the position graphs for the quadratic? We wrote out what they could be on the board but didn't come upon a definite answer.  They could represent velocity, speed, or acceleration but I think we should all come to an agreement and maybe do another lab with the ramp to go more into depth and be more accurate with our answers.

Motion Maps

Motion maps are yet another way of showing an object's motion. The image below displays a motion map:

(via https://salttheoats.wordpress.com/category/motion-maps/)

The labels show what the different elements of a motion map are.  The x represents a reference point and the thick black line shooting from the x shows the position.  The white circles represent the object's position in relation to the vector.  The arrows coming from the white circles are the object's velocities at that position and time.  Each white circle and arrow is documented by a time interval (usually seconds).  In class, we created motion maps and graphs based off of data given that was displayed in other types of graphs or a written description.  Were there certain graphs that didn't provide enough data to create the others?

Velocity vs Time and Position vs Time Reflection

This we created velocity vs time graphs and position vs time graphs then labeled how distance, time, displacement, velocity, and position could be found on them.  Our graphs looked like this:



We used the equation for velocity (D/T) and re-wrote it to find the displacement in our second graph, which we learned how to do last quarter with other types of equations (solving for one variable out of many variables in an equation).

After creating these, Battaglia gave us a situation with these types of graphs:



We used the methods from the first graphs to calculate different components of the situation.