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4 years ago

9

Compute the moon's centripetal acceleration in its orbit around the earth. Recall that the moon orbits the earth very 38 days an

d that it is about 240,000 miles from earth.
What force causes this acceleration?

1 answer:

wlad13 [49]4 years ago

6 0

Centripetal acceleration, Ac = V^2 / R.

V = tangential speed
R = radius of the orbit

V = 2πR / T

R = 240,000 miles
T = 28 days [ i am correcting what I think is an error, because the moon orbits the earth every 28 days]

V = 2π(240,000miles)*(1,609m/miles)/(28days*24h/day*3600s/h)

V = 1,002.9m/s

Ac = V^2 / R = 0.0026 m/s^2

The force that cauces this acceleration is the gravity of our planet, as stated Lord Isaac Newton.

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3 years ago

A wagon wheel consists of 8 spokes of uniform diamter, each of mass m, and length L. The outer ring has a mass m rin. What is th

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Answer:

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The moment of inertia of the wheel through an axis through the center and perpendicular to the plane of the ring is $L^2(\dfrac{8m}{3}+m_r)$ .

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3 years ago

Describe two ways to change the frictional force between two solid surfaces.

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4 years ago

A nail driven into a board increases in temperature.

denis23 [38]

Answer:

ΔT = 40.91 °C

Explanation:

First we find the kinetic energy of one hit to the nail:

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where,

K.E = Kinetic energy = ?

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v = speed of hammer = 7.7 m/s

Therefore,

K.E = (1/2)(1.6 kg)(7.7 m/s)²

K.E = 47.432 J

Now, for 10 hits:

K.E = (10)(47.432 J)

K.E = 474.32 J

Now, we calculate the heat energy transferred (Q) to the nail. As, it is the 59% of K.E. Therefore,

Q = (0.59)K.E

Q = (0.59)(474.32 J)

Q = 279.84 J

The change in energy of nail is given as:

Q = mCΔT

where,

m = mass of nail = 7.6 g = 0.0076 kg

C = specific heat capacity of aluminum = 900 J/kg.°C

ΔT = Increase in temperature = ?

Therefore,

279.84 J = (0.0076 kg)(900 J/kg.°C)ΔT

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3 years ago

The specific heat of soil is 0.20 kcal/kg*C and the specific heat of water is 1.00 kcal/kg*C. This means that if 1 kg of soil an

stiv31 [10]

Answer: The soil will be $4\°C$ warmer than the water.

Explanation:

The heat (thermal energy) absorbed can be found using the following equation:

$Q=m.C.\Delta T$

Where:

$Q$ is the heat

$m$ is the mass of the element

$C$ is the specific heat capacity of the material.

$\Delta T$ is the variation in temperature

<u>In the case of soil we have:</u>

$Q_{soil}=m_{soil}.C_{soil}.\Delta T_{soil}$ (1)

Where:

$Q_{soil}=1 kcal$

$m_{soil}=1 kg$

$C_{soil}=0.2 kcal/kg \°C$

$\Delta T_{soil}$

<u>In the case of water we have:</u>

$Q_{water}=m_{water}.C_{water}.\Delta T_{water}$ (2)

Where:

$Q_{water}=1 kcal$

$m_{water}=1 kg$

$C_{water}=1 kcal/kg \°C$

$\Delta T_{water}$

Isolating $\Delta T$ from both equations:

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$\Delta T_{soil}=5\°C$ (4)

$\Delta T_{water}=\frac{Q_{water}}{m_{water}.C_{water}}$ (5)

$\Delta T_{water}=\frac{1 kcal}{1 kg(1 kcal/kg \°C)}$

$\Delta T_{water}=1\°C$ (6)

Comparing (4) and (6) we can find the soil will be $4\°C$ warmer than the water.

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4 years ago