Unit 3 Blog post

Unit 3 began with the introduction of Newton's 3rd law which states that every action in and action reaction pair has an equal and opposite reaction. Example when you run you push the ground back and the ground pushes you forward. This law is what allows us to move. In a horse carriage the force the horse pushes the ground with is stronger than the force the wheels push the ground with. This push against the ground creates  friction and the wheels have less friction which allows the carriage to move forward. We then moved on to the subject of tides. 

This video is a very good demonstration on how the moon's cycle affects the tides on earth. To get a visual moving cycle helped me understand what exactly happened. This video also differentiates the high and low tide cycles by color. As you can see the high tide starts off as light blue and pulls in as the moon shifts spots, same goes with the dark blue tides. It was very helpful to see the movement of earth's bulge during a 28 day cycle. 

Now this video gives more specifics on how the forces are pulling earth and it's tides. The side of earth directly facing the moon has the largest gravitational force(side 1). The side directly across earth has an equal and opposite force(side 2). Given the equation for the force between two objects F= g(m1xm2)/d^2, side two has less distance between the two objects (earth and moon) meaning there is a larger force. Distance and force are proportional. Side two has an larger distance and a equal and opposite force in the other direction. Say the force between earth and side 1 is 5, the force between earth and side 2 would be -5, a negative force simply means in the opposite direction.  This is why we see equal stretches in bulge from both sides. The earth rotates on an axis so every 6 hours the tides will change from low to high tides. Tides are highest at the new and full moon. These high tides are spring tides the force between earth and the moon are at their greatest. When the moon is half waxed and half wained the tides are still pulled by the moon but are still relatively low. The tides draw from the high tides on the other sides and add to their low tides creating neap tides. Neap tides are always slightly higher than the low tides. It is important to notice that even thought the force of the sun is stronger than the moons that because the greater increase in distance that we mostly feel the moons instead. After learning about tides we moved on to conservation of momentum. Momentum is the change in force over time. impulse is the change in momentum.  In a collision the change of momentum is the final momentum minus the initial momentum. In order to find momentum you must multiply an objects mass by its velocity.  Impulse is measure in Newton's seconds and momentum is measure in kilograms meters per second. To find the exact force at a period in time you take the change in momentum over the specific time.