(a) For BCC iron, compute the radius of a tetrahedral interstitial site. (See the result of 4.9.) (b) Lattice strains are imposed on iron atoms surrounding this site when carbon atoms occupy it. Compute the approximate magnitude of this strain by taking the difference between the carbon atom radius and the site radius and then dividing this difference by the site radius.

PY 205 Week 3 Notes Chapter 4 and 5 Newton’s Laws 1. Velocities don’t change unless a net force acts upon it (qualitative) 2. The acceleration of a body is directly proportional to the net force acted on it (quantitative) a. Fnet = (mass)(acceleration) 3. Forces occur between two objects – if A exerts a force on B then B exerts a negative force on A. a. Fnet = Fxi +Fyj + Fzk b. The sum of all the forces on x = ma(x) c. The sum of all the force on y = ma(y) Applications of Newton’s laws - Kinetic motion - sliding friction - The force acts opposite to the direction of the object’s velocity - Normal force = shows that the friction force is approximately proportional to the normal force – the