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ikadub [295]
4 years ago
15

As you stand by the side of the road, a car approaches you at a constant speed, sounding its horn, and you hear a frequency of 8

0.0 Hz. After the car goes by, you hear a frequency of 60.0 Hz. What is the speed of the car
Physics
1 answer:
kap26 [50]4 years ago
5 0

Answer: velocity of the car is 113.33m/s

Explanation:

From Doppler effect,

in the case which the source is moving towards the observer at rest

f2 = v/(v-vs) *f1

where f2 is the final observed frequency

f1 is the initial observed frequency

v = 340m/s (speed of sound in air)

vs = velocity of the source of sound.

rearranging the above equation

f2*(v - vs) = f1* v

vs = (f1* v/f2) - v

but f1 = 80Hz

f2 = 60Hz

v = 340m/s

substituting,

vs = (80 x 340)/60 - 340

vs = 453.33 - 340

vs = 113.33m/s

velocity of the car is 113.33m/s

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A damped harmonic oscillator consists of a block of mass 2.5 kg attached to a spring with spring constant 10 N/m to which is app
Cerrena [4.2K]

Answer:

0.5% per oscillation

Explanation:

The term 'damped oscillation' means an oscillation that fades away with time. For Example; a swinging pendulum.

Kinetic energy, KE= 1/2×mv^2-------------------------------------------------------------------------------------------------------------(1).

Where m= Mass, v= velocity.

Also, Elastic potential energy,PE=1/2×kX^2----------------------------------------------------------------------------------------------------------------------(2).

Where k= force constant, X= displacement.

Mechanical energy= potential energy (when a damped oscillator reaches maximum displacement).

Therefore, we use equation (3) to get the resonance frequency,

W^2= k/m--------------------------------------------------------------------------------------(3)

Slotting values into equation (3).

= 10/2.5.

= ✓4.

= 2 s^-1.

Recall that, F= -kX

F^2= (-0.1)^2

Potential energy,PE= 1/2 ×0.01

Potential energy= 0.05 ×100

= 0.5% per oscillation.

6 0
3 years ago
How does the conservation of energy effect our lives?
kupik [55]

Answer:

The Good with the Bad

What do eating a large delicious meal, taking out a loan to buy a car, and staying up all night to finish a paper have in common? They're all things that produce a good result or make us happy, but also have some negative consequences (gaining weight, going into debt, and being tired respectively). Everything in life has negative and positive consequences. Energy conservation is no different. In this lesson, we will learn more about the intended and unintended consequences of energy conservation.

Intended Consequences of Energy Conservation

In light of air pollution, the overuse of fossil fuels, and other issues efforts to conserve energy have been ramped up in the last few decades. Energy conservation can refer to reducing the amount of energy used or finding alternatives to traditional energy sources. There are several ways to conserve energy.

Recycling

Recycling involves making new products out of already existing material. This method of energy conservation works by taking already formed material and processing it into something new. It takes much more energy to create material from scratch than to make it from recycled material. For example, it takes 30% less energy to make recycled glass than to make brand new glass.

Reducing Energy Use in Homes

We can conserve energy in our homes by unplugging and turning off lights and appliances when they are not in use. Obviously, there are some exceptions. Please don't go unplugging your refrigerator! However, many appliances like coffee makers and cell phone chargers can be unplugged when you're not using them. Homeowners can also better insulate their homes to reduce heat usage. Energy can also be conserved by buying appliances that are designed to be energy efficient. Both of these strategies save consumers money on their electric bills, so it's a win-win situation. Using less power overall reduces the pollution from power plants. When we use less energy in our homes, the power plants need to burn less fossil fuels. Burning less fossil fuels reduces pollution and helps conserve natural resources.

Save the Animals

As mentioned above, when consumers use less energy, less fossil fuels need to be burned. When the demand for fossil fuels is reduced, there is less drilling for oil and extraction of resources from nature. Less extraction from the environment results in less damage to habitats and ecosystems. When there are less fossil fuels used, there is also a reduction in oil spills in the oceans and in toxic waste produced from power plants. All of these factors benefit animals and the environment because they are disturbed less.

In this section we will discuss three specific energy conservation efforts and their unintended consequences.

Wind Power

Wind Power involves the use of large turbines (blades) that turn wind into useful energy. Wind turbines can take up large areas of land. While that land can often be shared due to the largest part of the turbines being in the air, flying birds and bats can be killed by spinning turbines. It seems pretty logical to place wind turbines near oceans since shore areas are often windy. However, the turbines can disrupt the habitats due to the space they take up and the danger they pose to flying animals. Another issue is that wind turbines can be annoying to the people who live near them. Some people have reported issues with sound and vibration from the turbines.

8 0
3 years ago
A hiker walks due east for a distance of 25.5 km from her base camp. On the second day, she walks 41.0 km northwest till she dis
GarryVolchara [31]

Resultant displacement is 29.2 km at 83.1^{\circ} north of west

Explanation:

To solve the problem, we have to use the rules of vector addition, resolving first each vector along the x- and y- direction.

Taking east as positive x direction and north as positive y- direction, we have:

- First displacement is 25.5 km east, therefore its components are

A_x = 25.5 km\\A_y = 0 km

- Second displacement is 41.0 km northwest, so its components are

B_x = (41.0)cos(135^{\circ})=-29.0 km\\B_y =(41.0)sin(135^{\circ})=29.0 km

So, the components of the resultant displacement are

R_x=A_x+B_x=25.5+(-29.0)=-3.5 km\\R_y=A_y+B_y=0+29.0=29.0 km

And so, the magnitude is calculated using Pythagorean's theorem:

R=\sqrt{R_x^2+R_y^2}=\sqrt{(-3.5)^2+(29.0)^2}=29.2 km

And the direction is given by

\theta=tan^{-1}(\frac{R_y}{|R_x|})=tan^{-1}(\frac{29.0}{3.5})=83.1^{\circ}

Where the angle is measured from the west direction, since Rx is negative.

Learn more about displacement:

brainly.com/question/3969582

#LearnwithBrainly

3 0
3 years ago
4.
Pie

Answer:

b

Explanation:

it compresses hot air turning into cool air almost like a reverse tornado

3 0
3 years ago
Read 2 more answers
What forms when air masses with different temperatures meet?
WARRIOR [948]
Clouds and fog and it may rain or snow
7 0
3 years ago
Read 2 more answers
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