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4 years ago

What force causes the periodic motion of a pendulum?

2 answers:

7 0

the answer of this question is option A because,

Pendulum. If you swing a weight on a string, it will go back and forth in regularperiodic motion. ... The force of gravitycauses the pendulum bob to change directions, while the force from the string moves it in a semi-circular motion

borishaifa [10]4 years ago

5 0

Answer:

the Answer is A

Explanation:

because the swinging motion of a pendulum is due to the force of gravity generated by the earth's size

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Calculate the density of each ball. Use the formula

Paraphin [41]

Answer:

⇒ 0.07 g/cm3

⇒ 1.15 g/cm3

Explanation:

3 0

3 years ago

Read 2 more answers

Air is compressed from 14.7 psia and 60°F to a pressure of 150 psia while being cooled at a rate of 10 Btu/lbm by circulating wa

iren2701 [21]

Answer:

A. 6.36 lbm/s

b. $T_2=341\textdegree F$

Explanation:

a. Given the following information;

#Compressor inlet:

Air pressure, $P_1=14.7psia,T_1=60\textdegree F$

#Compressor outlet:

$Air \ Pressure, P_2=150psia\\\\Air \ volume \ flow \ rate, \dot V_1=5000ft^3/min$

#Cooling rate,

$q_{out}=10Btu/lbm, \dot W=700hp$

# From table A-1E

Gas constant of air $R=0.3704\ psia.ft^3/lbm.R$

Specific enthalpy at $P_1=520R-h_1=124.27Btu/lbm$

Using the mass balance:

$\dot m_{in}-\dot m_{out}=\bigtriangleup \dot m_{sys}=0.0\\\\\dot m_{in}=\dot m_{out}\\\\v_1=\frac{RT_1}{P_1}\\\\v_1=\frac{0.3704\times520}{14.7}\\\\\\v_1=13.1026ft^3/lbm\\\\\dot m=\frac{5000/60}{13.1025}\\\\\dot m=6.36\ lbm/s$

Hence, the mass flow rate of the air is 6.36lbm/s

b The specific enthalpy at the exit is defined as the energy balance on the system:

$\dot m_{in}-\dot m_{out}=\bigtriangleup \dot m_{sys}=0.0\\\\\dot m_{in}=\dot m_{out}\\\\\dot W_{in}+ \dot mh_1=\dot Q_{out}+\dot m_2\\\\h_2=\frac{\dot W_{in}-\dot Q_{out}}{\dot m}+h_1\\\\h_2=\frac{700\times 0.7068-10\times 6.36}{6.36}+124.27\\\\h_2=192.06\ Btu/lbm\\\\#at \ h_2=182.06Btu/lbm, T_2=801R=341\textdegree F$

Hence, the temperature at the compressor exit $T_2=341\textdegree F$

5 0

4 years ago

Why do all planets rotate around the sun in the ssame direction

Nutka1998 [239]

This is because of the conservation of angular momentum, which allows most planets to spin in the same direction, but Venus and Uranus have seem to ignore this as they spin in different directions, as Venus spins clockwise and Uranus is on its side

3 0

3 years ago

How could you work out the direction that the motor will turn

IgorLugansk [536]

If you mean work out as in using calculations, I don't know how to help you. But there is a way to find out, using Fleming's left hand rule. I can't define it properly, and I don't want to copy-paste from another site, so I strongly recommend that you look it up. Try google, or more specific, BBC GCSE bitesize.

Hope this helps!

5 0

3 years ago

Read 2 more answers

engine emits sound uniformly in all directions, radiating an acoustic power of 3.65 × 10 5 W. 3.65×105 W. Find the intensity of

Art [367]

Answer:

130.2dB

Explanation:

The formula for determining the intensity of a wave is expressed as

$I=\frac{P}{A}\\$