1. Notes: Monday, December 17, 2012 Topic: Newton’s Second Law EQ: How are Acceleration, Net Force, and Mass Related to one another?

2. Net Force Causes Acceleration Any net force acting on an object will cause it to accelerate. Net Forces are sometimes called unbalanced forces. Acceleration is when an object changes it’s speed and/or direction. To increase the acceleration on an object you must increase the net force on it.

3. Check for Understanding If I have an object accelerating at 13 [m/s 2 ] while under a net force of 3 [N]. Calculate the acceleration on the object if I double the net force on the object.

4. On Your Own I have a plane with a thrust of 20,000 [N] of force on it which makes it accelerate at 10 [m/s 2 ]. If I cut the thrust in half how fast will the plane accelerate? I launch a cannon with a force of 450 [N], and the cannonball accelerates with 100 [m/s 2 ]. If I increase the force to 900 [N], what will the acceleration on the cannonball be?

5. Mass Resists Acceleration For a constant net force, an increase in the mass will result in a decrease in the acceleration. These are called inversely proportional

6. Check for Understanding If I have a shopping cart with a mass of 45 [kg] which is accelerating with 2 [m/s 2 ]. If I drop 45 [kg] of rice into the cart, what will the be of the resulting acceleration of the shopping cart?

7. On Your Own If a cargo plane, of mass 30,000 [kg] is accelerating with 30 [m/s 2 ] and suddenly drops 15,000 [kg] of it’s payload, what is the resulting acceleration? If a boat, of mass 1000 [kg] is accelerating at 15 [m/s] and someone on a bridge above it drops 2000 [kg] of material on the boat. What will the boat be accelerating at?

8. Newton’s Second Law The acceleration produced by a net force on an object is directly proportional to the magnitude of the net force, is in the same direction as the net force, and is inversely proportional to the mass of the object.

9. Reflection How are Acceleration, Net Force, and Mass Related to one another?