Q1. A piece of wood is 6.00 m long, 0.260 m wide and 0.060 m thick. Its density is 600kg/m cubed. What volume of iron ( P iron = 7.8 x 10 cubed kg/m cubed) must be fastened underneath the wood to sink it so that the top surface of the wood is just even with the water (P water = 1.00 x 10 cubed kg/m cubed) level?

Q2. A 1.70 MHz sound wave travels through a pregnant woman's abdomen and is reflected from the fetal heart wall of her unborn baby. The heart wall is moving toward the sound receiver as the heart beats. The reflected sound is then mixed with the transmitted sound, and 85 beats per second are detected. The speed of sound in body tissue is 1500 m/s.

Calculate the speed of the fetal heart wall at the instant this measurement is made.