# Week 4

**Reading:**PSE Chap 3, Vectors

**Topics:**introduction to vector algebra

**Lab:**Ramp experiment

**Homework Problems:**Due next Wednesday, Sept. 14, at noon.

- The vector problem assigned by Zeke and Michael .
- Three strings are attached to a small gold ring. One string pulls eastward with a force of 4 lbs. The second string pulls northward with a force of 7 lbs. The third string pulls southwestward with a force of 5 lbs. (a) First, express the net force as a vector with appropriate components (
*i.e.,*east, north, west, south). (b) Now: what is the magnitude of the net force on the ring? (c) Finally, what is the angle that the net force makes (compared to the eastward direction) . Solution. - Submit your laboratory notebook pages form the ramp laboratory experiment. Be sure to plot the position of the ball as a function of time. Explain your plot. Does the ball undergo uniform acceleration? If not, why not? How might you do this experiment better?

**Quiz:**None during week 4. We will have a quiz on Monday of week 5.