1. PHYS 101 Newton’s second law

2. Example 1 A sled with a mass of 20kg slides along frictionless ice at 4.5 m/s. It then crosses a rough patch of snow that exerts a friction force of f = 12 N (kinetic or static?). How far does the sled slide before it comes to rest?

3. Example 2 Students help you move into you dorm and push your boxes up a 20° slope with a horizontal force. How hard do they have to push to get the box moving? Could they make their lives a bit easier?

4. mass vs. weight Moon Olympics note: John Young’s weight is still stated as 300 pounds …