How many quark colors are there?
a. 1 c. 6
b. 3 d. none of the above
B
You might also like to view...
Consider a vertical 20-cm-tall flat plate at 120°C suspended in a fluid at 100°C. If the fluid is being forced past the plate from above, estimate the fluid velocity for which natural convection becomes negligible (less than 10%) in: (a) mercury (b) air (c) water.
GIVEN
? A vertical flat plate suspended in a fluid
? Plate temperature (Ts) = 120°C
? Fluid temperature (T?) = 100°C
? Fluid is being forced past the plate from above
? Plate height (H) = 20 cm = 0.2 m
FIND
? The fluid velocity (U?) for which natural convection has a less than 10% effect in
(a) mercury (b) air (c) water
ASSUMPTIONS
? Steady state
SKETCH
PROPERTIES AND CONSTANTS
From Appendix 2, Tables 26, 28 and 13
An unknown tuning fork is sounded along with a tuning fork whose frequency is 256. Hz and a beat frequency of 3. Hz is heard. What is the frequency of the unknown tuning fork?
A) It must be 256 Hz. B) It must be 259 Hz. C) It could be either 253 Hz or 259 Hz; there is no way to tell. D) It must be 253 Hz.
A 0.50-kg box is attached to an ideal spring of spring constant 20 N/m on a horizontal, frictionless floor
The box oscillates in simple harmonic motion and has a speed of 1.5 m/s at the equilibrium position. (a) What is the amplitude of vibration? (b) At what distance from the equilibrium position are the kinetic energy and the potential energy the same?
A lawn mower has a 6-horsepower engine (1 HP = 750 W). If the engine has an efficiency of 20%, and the throttle is such that the engine cycles 10 times a second, the heat that is expelled in one cycle is
a. 1 800 J b. 2 000 J c. 2 200 J d. 2 400 J e. 2 250 J