1. Mrs. Border’s Science Class

2. Essential question The size of air resistance force depends on what two variables?

3. Newton’s Second Law Newton’s second law of motion connects force, acceleration, and mass; it explains that an object acted upon by a force will accelerate in the direction of the force; acceleration equals net force divided by mass. Respectively then we can say, F= MxA A= acceleration F= Force M= Mass

4. Check for understanding So what is Newton’s 2 nd law? An object acted upon by an unbalanced force will accelerate in the direction of the force according to

5. Newton’s Second Law Gravity- attractive force between two objects; depends on the mass of the objects and the distance between them; gravitational force is also called weight. The 2 nd law explains how to calculate the acceleration of an object if its mass and the forces acting on it are both known.

6. Newton’s Second Law In a circular motion, the centripetal force is always perpendicular to the motion.

7. Newton’s Second Law The terminal velocity is reached when the force of gravity is balanced by air resistance; the size of the air resistance force depends on the shape of an object and its speed. An object can speed up, slow down, or turn in the direction of the net force when unbalanced forces act on it.

8. Essential question The size of air resistance force depends on what two variables? Shape of an object and its speed

9. Practice problems Remember 1. A net force of 4,500 N acts on a car with a mass of 1,500 kg. What is the acceleration of the car? 2. A book with a mass of 2.0 kg is pushed along a tabel. If the net force on the book is 1.0 N, what is the books acceleration