1. Welcome back to 2014! Physics 11

2. Force of Gravity A student lifts her Christmas presents high above her head. She need to exert a force of 775 N to overcome gravity. a) Determine the mass of her presents. b) How much force would she need to exert if she was on the Jupiter (g = 24.5 m/s 2 ) c) She now finds herself on the surface of the Sun and finds that she needs to exert a force of 20 800 N. What is the acceleration due to gravity on the Sun? F g = mg

3. A student lifts her Christmas presents high above her head. She need to exert a force of 775 N to overcome gravity. a)Determine the mass of her presents. b) How much force would she need to exert if she was on the Jupiter (g = 24.5 m/s 2 ) c) She now finds herself on the surface of the Sun and finds that she needs to exert a force of 20 800 N. What is the acceleration due to gravity on the Sun?

4. Newton’s 2 nd Law “If a body is acted upon by an unbalanced force, it will accelerate.” F net = ma Example: Rudolph exerts a force of 8.50x10 3 N east, while friction pulls back on him with a force of 1500 N. If he has a mass of 85 kg, what is its acceleration?

5. Example:

6. Free Bodied Diagrams Santa rests his sack of toys upon his shoulder. The sack is suspended motionless by one strap from one shoulder. Diagram the vertical forces acting on the bag of goodies. A force is applied to the right to drag a sled across loosely-packed snow with a rightward acceleration. Diagram the forces acting upon the sled.

7. Newton’s First Law “An object in motion will stay in motion and an object at rest will stay at rest, unless an outside force is applied to it.” Inertia! Example: Santa’s 925 kg sleigh accelerates uniformly from rest to a velocity of 25.0 m/s south in 10.0 s. What is the net force acting on the car during this acceleration?

8. Example: Santa’s 925 kg sleigh accelerates uniformly from rest to a velocity of 25.0 m/s south in 10.0 s. What is the net force acting on the car during this acceleration?