1. Using Newton’s Laws

2. Using Newton’s Laws
Identify objects of interest
Draw free-body diagram
Write Newton’s 2nd Law
Choose coordinate system
Write out forces in chosen coordinates
Solve equations symbolically
Check the sense of the problem
Insert the values for numerical answers

3. Frictional Force
Frictional force is parallel to the surface and opposes the tendency of the object to move.
Static Coefficient of Friction - ms
Kinetic Coefficient of Friction - mk N T Ff W

4. Block with Friction
A 1.1 kg block is at the top of a 3.4 m long ramp that is at an angle of 20°. If the static coefficient of friction between the block and the ramp is 0.40, will the block move? If the kinetic coefficient of friction is 0.30, will it remain moving? q

5. Rounding the Curve
Ex. A car travels around a curve of radius 120 m at 24.5 m/s. If the car has a mass of 750 kg, what is the force of the road on the tires of the car?

6. Banked Curve
One curve between Cedarville and Jamestown has a radius of curvature of 120 m. What angle would you place on the road bed so that a car traveling 13 m/s would not slide out even if there was a glaze of ice?

7. Accelerated Reference Frames
You are seated in a railroad boxcar. You notice that the twine attaching the lantern to the ceiling makes an angle of 12° with respect to vertical. What is happening to the boxcar?

8. Resistive Forces Force proportional to velocity
Resistive constant, b
Terminal velocity, vt
Force proportional to velocity squared
Drag coefficient, D
Density of air, r

9. Skydiving
A 100 kg man wears a suit that gives him an effective area of 1.5 m2. If his drag coefficient is 0.5, what is his terminal velocity?
If he wants a terminal velocity of 5.0 m/s after his chute deploys, what must be its area?