# Week 11 (Mar. 25 - 29)

**Read:**Newton's Laws of Motion (ASGv2 Chap. 21).

**Key topics:**newton's laws of motion, force addition, action-reaction pairs, free body diagrams,

**PHY 201 Lecture:**None; easter Break begins on Thursday.

**Quiz:**covering week 10.

Homework:

Homework:

- Momentum and Force (Ex. 21.1),
- Bull-train collision (Ex. 21.2),
- Action-reaction pairs (Ex. 21.3)
- Two astronauts play tug-of war in outer space. Astronaut A has a mass of 200 kg. Astronaut B has a mass of 150 kg. Astronaut A pulls the rope connecting them with a force of 20 Newtons. (a) What is the acceleration of astronaut B? (b) What is the force acting on astronaut A? (c) What is the acceleration of astronaut A? (d) If the rope is 100 meters long when do the astronauts hit each other?
- A100 gram hockey puck slides across the ice at a speed of 10 m/s due east. A hockey player strikes the puck with a force of 30 Newtons for 0.01 seconds. The force is directed due west. What is the final velocity of the puck after the force is done acting? What if the force, instead was directed due north?

**Lab:**None. Easter break begins on Thursday.

**Chapter 21:**These four videos introduce Newton's three laws of motion.

**In the next 13 videos, I walk you through the lab that we will be doing next week; Professors Kuehn and Schindler recorded ourselves carrying out this lab in the spring of 2020. Professor Schindler tells some jokes. I highly recommend watching these videos before coming to lab next week.**

Force and Rotation Lab:

Force and Rotation Lab: