1. {B} The formula P = k'r2T4 , where k is a constant, describes the dependence of power radiated (P) by a glowing sphere on its radius {r} and temperature {T}. (a) Which combination of powers of P and T are directly proportional (i.e., which set of axes would you choose to make a linear curve?) {b} If the sphere radius stays constant, and temperature changes, from 325 K to 400 K, by what factor does power grow or shrink? {c} Which combination of powers of r and T are directly proportional {i.e., which set of axes would you choose to make a linear curve?) (d) If the output power stays constant, and temperature changes, from 325 K to 400 K, by what factor does sphere radius grow or shrink? 2. (4) A small aeroplane moves at 265 km/h relative to the ground, 45 E of N. The wind is blowing at 37 km/h at 70 N of W. What is the magnitude and direction (in degrees) of the aeroplane's airspeed?3. [3] Go to randomorg and obtain four random numbers from 25 to +25. Use them as the x -i t- and v components of two vectors A, and B, respectively. 3:: :uu: :n [a] Show ii e\