11/14 MS physics update and homework due 11/21

Hi folks,

First off, next week is the last week of this trimester so please try to get any missing homework in by next week.  If you're not sure if you are missing anything please email me and I'll get let you know if and what you're missing.

Second, next week's quiz will cover stuff from all the classes so far so be sure to look over all those old quizzes.  I'd recommend covering your old answers and retaking the quiz all over again.  That way you will really be able to know if you have mastered the material or not.  This week's homework is lighter to give you time to study.  You're welcome.  :)

Today we got a bit deeper into Newton's second law, F=MA.   Those four little symbols pack a lot of meaning, so I wanted us to spend a bit more time with the concept. To do so, we used Hot Wheels cars and a "Force-in-ator" to see what the effect of force and mass was on acceleration.  The students had to do some careful data collection in order to calculate the speeds of the cars.

For homework next week please answer the following questions.

1.  In today's lab, when you increased force, what happened to acceleration?

2.  In today's lab, when you increased mass, what happened to acceleration?

3.  Would you say force is directly or indirectly proportional to acceleration?  (In other words, does one go up while the other goes down or do both go up when one goes up.)

4.  Would you say mass is directly or indirectly proportional to acceleration?  (In other words, does one go up while the other goes down or do both go up when one goes up.)

For the following questions tell me how F, M and A can be found in the different scenarios.  For example, if the question was, "Tell me how F=MA can be applied to a baseball pitcher throwing a ball."  You could say that the force is the pitcher's arm, the mass is the ball and the acceleration is the ball speeding up.

5.  Tell me how F=MA applies to a batter hitting a ball.

6.  Tell me how F=MA applies to a soccer player kicking a ball.

7.  Tell me how F=MA applies to a car when it drives away from a stop light.

8.  Tell me how F=MA applies to a bike when it comes to a stop sign.

9.  Now you make up a scenario and tell me where F=MA applies to your scenario.

Answers:

1.  When force went up the cars accelerated more.  

2.  When went up the cars accelerated less.

3.  Since both force and acceleration went up they are directly proportional.  "Two thumbs up." 

4.  Since acceleration went down with mass went up they are inversely proportional.   "One thumb up and one down."

5.   F is the batter's arm muscles.  M is the mass of the ball. A is the ball changing speed.

6.  F is the soccer player's leg muscles.  M is the mass of the ball.  A is the ball changing speed.

7.  F is the engine of the car.  M is the mass of the car.  A is the car changing speed.

8.   F is the brakes on the bike causing friction.  M is the mass of the bike and the rider. A is the bike changing speed.

9.  This one will vary.  I hope you come up with some good ones!