# Week 6

**Read:**From Conic Sections to Projectile Motion (ASGv2 Chap. 11) and The Speed and Force of a Projectile (ASGv2 Chap. 12).

**Key topics:**two-dimensional kinematics, projectile motion

**Homework:**

- Archery (Ex. 11.2a),
__Soccer problem:__A soccer player kicks a ball with an initial speed of 4 m/s at an angle of 30 degrees above the horizontal. How much time is the ball in the air before it lands on the ground? What is the maximum height the ball reaches? What is the ball's range? What is its velocity at the top of its flight (magnitude and direction)? What is its velocity at the moment it strikes the ground? And what is its velocity at the moment it is halfway up to its maximum height? Solution.__Artillery problem:__An ambitious artillery officer wishes to fire a projectile from ground level so that it goes through a small window in a distant tower. The window is 30 meters above ground level. The tower is 8 kilometers from the launch point. The gun is aimed 30 degrees above the horizontal. What must be the muzzle velocity so that the projectile goes into the window? Assume that there is no wind or other drag acting on the projectile while in flight. Solution.- Castaway physics (Ex. 12.1),
- PHY 201: Geometry (Ex. 11.1),
- PHY 201: Archery (Ex. 11.2b),
- PHY 201: Terminal velocity (Ex. 11.3)
- PHY 201: Suppose the position vector of a particle moving in 2-dimensions is given by < t, 5*t >. Find the velocity as a function of time. Sketch the trajectory.
- PHY 201: Suppose the position vector of a particle moving in 3 dimensions is given by < 2* cos(omega * t), 2 sin (omega * t), t^2>. Find the velocity as a function of time. Sketch the trajectory.

**Artillery (Ex. 11.4)**

Lab:

Lab:

**Chapter 11 & 12 (6 videos):**