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kykrilka
1 month ago
15

A clock has an hour hand of length 2.4 cm and a minute hand of length 3.8 cm. (a) Calculate the position and velocity of the hou

r hand at noon. (b) Calculate the position and velocity of the minute hand at 12:15.
Physics
1 answer:
Ostrovityanka [3.2K]1 month ago
6 0

Answer:

  1. At 12:00, the hour hand is positioned at 0 degrees, with its tip moving at an estimated 1.26 cm/hour.
  2. At 12:15, the minute hand is at 90 degrees, traveling at roughly 23.88 cm/hour.

Explanation:

The position is established by an angle, which begins at the 12:00 point and extends clockwise.

  1. At noon, the hour hand is at the 12:00 position, thus its position is 0 degrees; it has an angular velocity of (2π)/(12 hours) = π/(6 hours). Therefore, the tip moves at a linear velocity of (2.4 cm) * π/(6 hours) ≅ 1.26 cm/hour.
  1. At 12:15, the minute hand is at the 3 o'clock position, giving it a position of 90 degrees or π/2; its angular velocity is (2π)/(1 hour) = 2π/hour. Thus, the tip moves at a linear velocity of (3.8 cm) * 2π/hour ≅ 23.88 cm/hour.
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According to a rule-of-thumb. every five seconds between a lightning flash and the following thunder gives the distance to the f
ValentinkaMS [3465]

Answer:

S_{s}=300 m/s

According to the guideline for kilometers, every three seconds between a lightning strike and the subsequent thunder indicates the distance to the flash in kilometers.

Explanation:

To calculate the speed of sound in meters per second, we need to utilize certain conversion factors. One mile corresponds to 5 seconds after witnessing the lightning. Furthermore, 1 mile comprises 5280 feet, and 1 foot is equivalent to 0.3048 meters. This information is sufficient to solve the issue. The conversion ratios can be set up like this:

\frac{1mi}{5s}*\frac{5280ft}{1mi}*\frac{0.3048m}{1ft}=321.87m/s

Observe how the ratios are organized such that the units cancel out during calculations. One ratio has miles in the numerator while the other has them in the denominator, leading to cancellation. The same applies to the feet.

The question requires us to provide the answer to one significant figure, resulting in the speed of sound rounding to 300m/s.

For the second part, we will again utilize conversions. This time we will set our ratios in reverse and realize that there are 1000 meters in 1 kilometer, leading us to:

\frac{5s}{1mi}*\frac{1mi}{5280ft}*\frac{1ft}{0.3048m}*\frac{1000m}{1km}=3.11s/km

This signifies that for every 3.11 seconds, the distance to the lightning strike is 1 kilometer. Since this is a fabric of general knowledge, we round to the nearest whole number for simplicity, establishing the guideline:

According to the rule for kilometers, every three seconds between a lightning flash and the following thunder gives the distance to the flash in kilometers.

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1 month ago
What is the freezing point of radiator fluid that is 50% antifreeze by mass? k f for water is 1.86 ∘ c/m?
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Ethylene glycol is known as the main component found in antifreeze.
The molecular formula for ethylene glycol is C₂H₆O₂.
Its molar mass is calculated as C₂H₆O₂ = (2×12) +(6×1) + (216) = 62g/mol
Given that antifreeze comprises 50% by weight, there exists 1 kg of ethylene glycol mixed with 1 kg of water.
ΔTf = Kf×m
ΔTf refers to the change in the freezing point.
= starting temperature of water - freezing temperature of the solution
= 0°C - Tf
= -Tf
Kf stands for the freezing point depression constant of water, which is 1.86°C/m
m is the molarity of the solution.
=(mass/molar mass) where mass of solvent is in kg
=1000g/62 (g/mol) /1kg
=16.13m
Substituting the value into the equation gives us
-Tf = 1.86 × 16.13 = 30
thus Tf = -30°C
7 0
25 days ago
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For motion in a circle.

Centripetal acceleration is calculated as mv²/r = mω²r

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. Here, m is the mass of the object, which is 175g or 0.175kg.

The angular speed, ω, is derived from Angle covered / time

                         = 2 revolutions per 1 second

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. The acceleration's magnitude is approximately 13.817  m/s² and it is oriented towards the center of the circular path.

The tension in the string equates to m*a

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Maru [3345]

Answer:

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d = Slit spacing = 6 μm

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Answer:

50 meters

Explanation:

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