1. A spring stretches 5.0 cm when a 200.-gram mass is hung from it and set to equilibrium. What is its spring constant?

2. When that spring in its unstretched state, if that mass is hung on the spring and
immediately let go, what will be the period (duration) of its oscillations?

3. A pendulum clock has a two-foot-long pendulum. The gears of the clock should be
calibrated so that how many cycles of the pendulum cause the clock hands to advance one
minute?

Athin electrical heater is inserted between a long circular rod and a concentric tube with inner and outer radii of 20 and 40 mm. the rod (a) has a thermal conductivity of ka = 0.15 w/(m*k), while the tube (b) has a thermal conductivity of kb = 0.8 w/(m*k) and its outer surface is subjected to convection with a fluid of temperature t= -15°c and heat transfer coefficient 60 w/(m2 *k). the thermal contact resistance between the cylinder surfaces and the heater is negligible. (a) determine the electrical power per unit length of the cylinders (w/m) that is required to maintain the outer surface of cylinder b at 15°c. (b) what is the temperature at the center of cylinder a?