From Autumn 99
1. A merry-go-round rotates at the rate =1.2 rad/s with a man of mass m = 80 kg standing at a point ri = 2.0 m from the center-axis of rotation.
See Figure 1.
(a) Iiwi = Ifwf
(m(R/2)2 + ½MR2 )wi= (mR2
2. (20 points)
A block of wood floats partially submerged in a lake. The cross-sectional area of the block is A, the total height of the block is 2.0 m and the density of the wood is 650 kg/m3. Assume the lake water has density 1000 kg/m3 . See the diagram below. What is the height H of the top face of the block above the water surface?
|Mg = FB
650*A*2.00*g = 1000*A*(2 - H)g. Solve for H.
3. (20 points)
A brass ring is to be fitted over a cylindrical brass shaft whose diameter is D2 =3.212 cm at 250C. The inner diameter of the ring is D1 = 3.196 cm at 250C. See the diagram below.
To what temperature must the shaft be cooled before it will slip into the ring? The linear coefficient expansion of brass is
4. (20 points)
An ice cube at initial temperature -10.0 0C and mass m is placed in water with mass M = 650 g and initial temperature 25.0 0C. The final equilibrium temperature of the mixture is 3.0 0C.
What is the mass m of the ice cube? Show all work!
5. (24 points)
A 6.0-kg block of aluminum is cooled from 950C to 250C at atmospheric pressure. The density of the aluminum is 2700 kg/m3. The linear expansion coefficient of aluminum is 24.0x10-6 (oC)-1 . The specific heat of aluminum is C = 900 J/kg 0C.
See hint to #20, Quiz 11. .
6. (20 points)
The motion of an object is described by the equation
See hint to #23, Quiz 12. .
7. ( 20 points) An outside stereo speaker at a ski resort emits sound waves with a power output of 90.00 W and frequency 1100.00 Hz.