|Hints to fix the most common mistakes in the packet:
Finding Frictional Forces:
- Don't forget that frictional forces always oppose motion, this means that the arrow for the frictional force will go the
opposite direction from the motion
Section Review 13.1 - p. 273
- 1 - give the place and the cause, both!
- 3 - remember 1 lb = 4.48 N
- 4 - 1kg = 9.8N (on Earth)
- 10 - Don't give me the mass (kg) give me the weight (N)
Section Review 13.2 - p. 281
- 2 - sound travels in all directions
- 6 - don't forget to label what each type of force is. (gravity, friction, normal, tension, compression, etc.)
- 8 - The swing is being held up by two ropes.
Concepts - p. 258
- 1 - this one is really tricky!! They are not the same object. Object 1 is on Earth and Object 2 is on the Moon, both have a
weight of 10N. Think about it.
- 3 - When the food moves down the belt, what kind of friction makes it move. (this is a reference point question)
- 7 - Just draw the vectors!
- 11 - Don't forget to label the forces.
Problems p. 286
- 4 - look at where the vector starts!
- 5 - give the normal force, in newtons