Physics 213 Test 2 12 pts each (4 pts absolutelyl free!) Oct. 10, 2003

1.

2. You observe a small electric powered car moving up a ramp with constant speed.

a. Make a two column table showing all the forces acting on the penguin and all the reaction forces to those forces.

b. What must be the net force acting on this car?

3. A 700 N fellow in the elevator is trying to see if he can reduce weight by weighing himself while riding in an elevator. What acceleration in which direction must the elevator have in order for the scales to read 600 N?

4. The block is at rest on the plane.

a. What must be the static friction force on the block?

b. If this static friction force has reached it’s maximum value and the block is on the verge of motion down the plane, what must be the static coefficient of friction between the block and the plane?

5. The surfaces are friction free. Find the magnitude and direction of the acceleration of the system.

6. Find the normal force on the 5 kg block.

7. What does each of the scales read in the picture below ?

8. A 400 N kid rides a Ferris Wheel at the circus. She is sitting on a scales, to see how her weight (according to the scales ) varies as she goes around. The Ferris Wheel has a radius of 40 m and she is moving with a constant speed . If the strap holding her in the seat must exert a force of 100 N down to hold her in the seat at the top of the ride,

a) How fast is she moving? (You must draw a FBD to receive any credit.)

b) What does the scales read at the bottom of the of the Ferris Wheel? (You must draw a FBD to receive any credit.)