physics final

a sphere radiates energy at a rate of 1.30 J.s when its temperature is 100 degrees Celsius. at what rate will it radiate energy it its temperature is increased to 200 degrees Celsius?

(Q1/Q2)=(T1/T2)^4

if there string is lengthened to 2m while the ball is being twirled then the speed of the ball will now be ________.

(original length/new length) * speed

if you now open the close end, the new fundamental frequency will be ____________.

*double the frequency given

Chlorine molecules are 35.5x more massive than hydrogen molecules. if the sample of these two gases are at the same temp, what must be true about the motion of the molecules?

-the average kinetic energy is the same for both gases. -the rms speed of the hydrogen molecules is sqrt(35.5) times greater than that of the chlorine molecules.

a horizontal cylindrical ice has a part with a diameter 1/4 that of the rest of the pipe. if v is the speed of the fluid in the wider section of pipe, then the speed of the fluid in narrower section is ________.

16v (1/4 squared take the reciprocal)

a spherical object has a density of P. if its compressed under high pressure to half of its original diameter, its density will now be

2** inverse relationship

A segment A of wire is stretch tightly between two posts a distance L apart vibrates at its fundamental mode with frequency f. A segment B of an identical wire is stretched with the same tension, but between two different posts. you observe that at the frequency of the second harmonic of wire B is the same are the fundamental frequency of wire A. the length of wire b must be _____.

2L

an object of mass M by a spring vibrates with a period T. if this object is replaced by one of mass 4M, the new object vibrates with a period ___________.

2T (take the sqrt)

an omnidirectional loudspeaker produces sound waves uniformly in all directions. the total power received by a sphere of radius 2m centered on the speaker 340W. a sphere with the radius 4m will receive a Total power of

340 W (does not change)

if it takes time T to make its first revolution, in times 6T the disk will make ______ revolutions.

36 (square the 6)

A cylindrical metal bar conducts heat at a rate R from a hot reservoir to a cold reservoir. If both its length and diameter are tripled it will conduct heat at a rate ______.

3R

A heavy solid disk rotating freely and slowed only by friction applied at its outer edge takes 120 seconds to come to a stop. if the disk had twice the radius and twice the mass, but the frictional force remained the same, the time it would take the wheel to come to a stop from the same initial rotational speed is ___________.

480 (2x2=4 (twice the radius and mass) *120=480)

if the gauge pressure at a depth in a lake is p, the gauge pressure at a depth 6d will be?

6p (pgauge=pgh)

if the rate of flow of the water in the narrow section is 8.0L/min, the flow of the water in the wide section is ______.

8.0 (it doesn't not change)

if all of the gas is put into a box having sides of length .5L without changing its temperature, the pressure it exerts on the walls of the larger box will be _____________.

8p (.5=1/2 cube 1/2=1/8 take the reciprocal)

to triple both the pressure and the volume of a fixed amount of an ideal gas, you would multiple its absolute temperature by_______.

9 (3x3 from tripling both)

what is the tension in the Achilles tendon?

=(force x cos(angle) x length of foot in m)/(length of tendon in meters)

The thermal conductivity of concrete is .8W, and the thermal conductivity of a certain wood is .1 W. how thick would a solid concrete wall have to be to have the same rate of heat flow as an 6 cm thick solid wall of this wood?

L1/L2=K1/K2

an insulated box has a barrier that confines a gas to only one side of the box. The barrier springs a leak, allowing the gas to flow and occupy both sides of the box. which statement best describes the entropy of this system?

The entropy is greater in the second state, with the gas on both sides of the box.

string is wrapped around the outer rim of a solid uniform cylinder that is free to rotate about a frictionless axle through its center. When the stringiest is pulled with a force P tangent to the rim, it gives the cylinder an angular acceleration a. if the cylinder had twice the radius, but everything else was the same , the angular acceleration would be _____.

a/2 *inversely proportional

If heat Q is required to increase the temperature of a metal object from 5-8 degrees Celsius, the amount of heat necessary to increase its temperature from 8 to 20 degrees Celsius is most likely ___________________.

answer is Q2/Q1 Q1=(8-5) Q2=(20-8)

what is the change in internal energy of gas?

delta U=Q(the heat absorbed)-W

you are standing between two stereo speakers that are emitting sound of wavelength 9.6 cm in step with each other. they are very far apart compared with that wavelength. if you start inn the middle and walk a distance x toward one speaker, you observe that the sound from these speakers first cancels when x is equal to ______.

divide wavelength by 4

if there change in internal energy of gas is negative the temperature goes _______________.

down

Find the vertical component of the force that the ankle join exerts on the foot?

force+tension*cos(angle)

if the absolute pressure at a depth d in a lake is p, the absolute pressure at a depth 9d will be ____.

less than 9P

use the components to find the magnitude of this force

sqrt((horizontal component)^2+(vertical component)^2)

if the angular velocity is w at the end of the first two revolutions, then at the end of the first four revolutions it will be _________.

sqrt(2) (4/2=2 take the sqrt of it)

if both the mass of the bob and the length of the pendulum are quadrupled, the new period will be ____.

sqrt(4)T

if both masses are now moved closer in so that each is d/9 from the rotation axis, while the angular velocity does not change, the kinetic energy of the system will be _________________.

square (1/9)

a spring mass system is undergoing simple harmonic motion of amplitude 2.1 cm and angular frequency 10.2 s^-1. the magnitude of the maximum acceleration of the mass as it oscillates back and forth is ___________.

square the angular frequency and multiply its by amplitude in meters

An object with mass M suspended by a spring vibrates with frequency F. when a second object is attached to the first, the system now vibrates with the frequency F/4. the mass of the second object is _____.

square the denominator-1

Find the horizontal component of the force that the ankle joint exerts on the foot?

tension*sin(angle)

what is true about the frequency and wavelength of this sound?

the frequency of the sound is given the wavelength= velocity of sound/frequency of sound

in terms of the thermodynamic cycle of this refrigerator, the electrical energy is equal to ____.

the work done on the gas

a thin metal rod expands 1.4mm when its temp is increased by 2 degrees Celsius. is an identical rod of the same material, except triple as long, also has its temp increased by 2 degrees celsius, it will expand ______.

triple the original expansion rate