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3 years ago

Revise this statement to make it true: Only winter is caused by the tilt of the earth's axis.

Physics

1 answer:

s2008m [1.1K]3 years ago

4 0

Answer:

Only winter is caused by the tilt of the earth's axis.False

it caused summer or autumn too

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What type of intermolecular force happens with a polar covalent molecule when dipoles are created due to un-equal sharing of ele

Semmy [17]

Answer:

Dipole-dipole interaction force

Explanation:

When one of the constituent atom of the covalent bonding is at least 1.5 times more electronegative than the other atom sharing the electron in the covalent bond then the shared pair of electrons are shifted towards the more electronegative atom developing a partial negative charge on it and similarly develops an equal partial positive charge on the other atom involved in the covalent bond.

This happens in water molecules and the resulting dipole is the cause of hydrogen bonding between two molecules of water. Hydrogen bond also exists in (HF) hydrogen fluoride molecules.

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4 years ago

An electrician must decide between 3 heaters. The wire that she is using is rated 15A maximum, anything beyond that is a fire ha

lutik1710 [3]

Use the formula: $P=IV$ , where P is power (watts), I is current (amperes) and V is potential difference (volts).

For the first heater:
$900W = I_{1}*120V$
$I_{1} = 7.5A$

For the second heater:
$1800W = I_{2}*120V$
$I_{2} = 15A$

For the third heater:
$3000W = I_{3}*240V$
$I_{3} = 12.5A$

6 0

3 years ago

An electric motor can drive grinding wheel at two different speeds. When set to high the angular speed is 2000 rpm. The wheel tu

shutvik [7]

a) The initial angular speed is 209.3 m/s

b) The angular acceleration is $-1.74 rad/s^2$

c) The angular speed after 40 s is 139.7 rad/s

d) The wheel makes 1501 revolutions

Explanation:

The initial angular speed of the wheel is

$\omega_i = 2000 rpm$

which means 2000 revolutions per minute.

We have to convert it into rad/s. Keeping in mind that:

$1 rev = 2\pi rad$

$1 min = 60 s$

We find:

$\omega_i = 2000 \frac{rev}{min} \cdot \frac{2\pi rad/rev}{60 s/min}=209.3 rad/s$

To find the angular acceleration, we have to convert the final angular speed also from rev/min to rad/s.

Using the same procedure used in part a),

$\omega_f = 1000 \frac{rev}{min} \cdot \frac{2\pi rad/rev}{60 s/min}=104.7 rad/s$

Now we can find the angular acceleration, given by

$\alpha = \frac{\omega_f - \omega_i}{t}$

where

$\omega_i = 209.3 rad/s$ is the initial angular speed

$\omega_f = 104.7 rad/s$ is the final angular speed

t = 60 s is the time interval

Substituting,

$\alpha = \frac{104.7-209.3}{60}=-1.74 rad/s^2$

To find the angular speed 40 seconds after the initial moment, we use the equivalent of the suvat equations for circular motion:

$\omega' = \omega_i + \alpha t$

where we have

$\omega_i = 209.3 rad/s$

$\alpha = -1.74 rad/s^2$

And substituting t = 40 s, we find

$\omega' = 209.3 + (-1.74)(40)=139.7 rad/s$

The angular displacement of the wheel in a certain time interval t is given by

$\theta=\omega_i t + \frac{1}{2}\alpha t^2$

where

$\omega_i = 209.3 rad/s$

$\alpha = -1.74 rad/s^2$

And substituting t = 60 s, we find:

$\theta=(209.3)(60) + \frac{1}{2}(-1.74)(60)^2=9426 rad$

So, the wheel turns 9426 radians in the 60 seconds of slowing down. Converting this value into revolutions,

$\theta = \frac{9426 rad}{2\pi rad/rev}=1501 rev$

Learn more about circular motion:

brainly.com/question/2562955

brainly.com/question/6372960

#LearnwithBrainly

8 0

3 years ago

Rahul sees a flock of birds. He watches as the flying birds land in neat little rows on several power lines. Which change of sta

Murljashka [212]

The change of state does the motion of the birds most closely model is deposition. Thank you for posting your question here at brainly. I hope the answer will help you. Feel free to ask more questions.

3 0

4 years ago

Read 2 more answers

A child has an ear canal that is 1.3 cm long. At what sound frequencies in the audible range will the child have increased heari

ElenaW [278]

Answer:

The answer to this is

6600 Hz to 19,800 Hz

Explanation:

The shape of the human ear is analogous to a closed ended pipe hence

we have λ = 4L or wavelength = 4 * length of the child ear

The frequency c/λ where c = speed of sound = 343 m/s

hence the child's audible range is multiples of 343/(4*0.13) =6600Hz

or 13200 Hz or 19,800 Hz

The generally quoted range of human hearing is 20 Hz to 20 kHz

7 0

3 years ago

Revise this statement to make it true: Only winter is caused by the tilt of the earth's axis.​

Revise this statement to make it true: Only winter is caused by the tilt of the earth's axis.