Worked out solutions to practice problems

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Homework for Tuesday's class

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A runner stars from rest and accelerates at 0.5 m/s/s for 10 seconds. If using the equations of motion is still tricky for you, be sure to set up the 4-step process: - What is known? - What are you looking for? - What is a relevant equation? - Solve it. 1.  What is her velocity after 10 seconds? 2.  How far does she go in this time? 3.  What would a graph of her distance vs. time look like?  Draw a rough approximation. 4.  What would a graph of her speed vs. time resemble?  Draw a rough approximation. Here is a reminder from today's class:
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Read before next class, if you have time.

MOMENTUM! We come up with momentum through Newton's 2nd Law: F = ma F = m  D v/t Rearranging: Ft = m  D v So this means that (on the left side) Force x time = (on the right side) mass x change in speed. Or simply: Ft = mv This interaction of force happens during a so-called "collision" or "explosion". Ft is defined as "impulse" and mv is defined as "momentum."   Note that the above equation helps explain how boxing gloves and airbags work – they increase the time of contact, thereby decreasing the average force delivered to the object. Please watch these clips: https://www.youtube.com/watch?v=3vDQm0qIYi0 https://www.youtube.com/watch?v=y3InF19dzlM Momentum  (which is the mv part of the above equation) is another way to describe (mathematically) how objects collide or explode – generally involving contact of some sort. p = mv No new unit here, just:   kg-m/s Momentum is...
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