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Vladimir [108]
3 years ago
7

A car traveling at 28 m/s starts to decelerate steadily. It comes to a complete stop in 13 seconds. What is its acceleration?

Physics
1 answer:
Maru [420]3 years ago
5 0

Acceleration = (change in speed) / (time for the change)

change in speed = (speed at the end) minus (speed at the beginning)

change in speed = (zero) minus (28 m/s) = -28 m/s

Acceleration = (-28 m/s) / (13 sec)

Acceleration = -2.15 m/s²

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At which position is the northern hemisphere experiencing winter?
Leto [7]

The answer would be point A.

Hope this helped you.

6 0
4 years ago
A team of engineering students is testing their newly designed 200 kg raft in the pool where the diving team practices. The raft
elena-s [515]

Answer:

The water level rises more when the cube is located above the raft before submerging.

Explanation:

These kinds of problems are based on the principle of Archimedes, who says that by immersing a body in a volume of water, the initial water level will be increased, raising the water level. That is, the height in the container with water will rise in level. The difference between the new volume and the initial volume of the water will be the volume of the submerged body.

Now we have two moments when the steel cube is held by the raft and when it is at the bottom of the pool.

When the cube is at the bottom of the water we know that the volume will increase, and we can calculate this volume using the volume of the cube.

Vc = 0.45*0.45*0.45 = 0.0911 [m^3]

Now when a body floats it is because a balance is established in the densities, the density of the body and the density of the water.

Ro_{H2O}=R_{c+r}\\where:\\Ro_{H2O}= water density = 1000 [kg/m^3]\\Ro_{c+r}= combined density cube + raft [kg/m^3]

Density is given by:

Ro = m/V

where:

m= mass [kg]

V = volume [m^3]

The buoyancy force can be calculated using the following equation:

F_{B}=W=Ro_{H20}*g*Vs\\W = (200+730)*9.81\\W=9123.3[N]\\\\9123=1000*9.81*Vs\\Vs = 0.93 [m^3]

Vs > Vc, What it means is that the combined volume of the raft and the cube is greater than that of the cube at the bottom of the pool. Therefore the water level rises more when the cube is located above the raft before submerging.

7 0
4 years ago
What is the Ozone layer?
yaroslaw [1]
"<span>a layer in the earth's stratosphere at an altitude of about 6.2 miles (10 km) containing a high concentration of ozone, which absorbs most of the ultraviolet radiation reaching the earth from the sun."

Hope this helps!
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4 0
3 years ago
Read 2 more answers
Please help me with this question, especially the angle part. I have solved the initial velocity already. I don't know what to d
Helga [31]
I think you almost got it.

At the top, the velocity only has horizontal component, so v=12 m/s is v_x, which is v*cos(theta), because v_x is constant, so the same when it was launched or now.

With the value of the initial speed (28 m/s, which is the total speed), you can set

v_x = v * cos( theta ) ---> 12 = 28*cos(theta) --> cos(theta)=12/28=3/7

or theta = 64.62 deg, it is D. Think about it. I hope you see it.
5 0
3 years ago
What occurs when the pitch increases and the sound source is in motion? explain your answer.
Hoochie [10]
If you're listening to a sound that has a steady pitch, and suddenly the
pitch goes up, then you know that two things could have happened:

EITHER ...

-- The person or other source making the sound could have
raised the pitch of the sound being produced.

OR ...

-- The person or other source making the sound could have
started moving toward you.

OR ...

-- both.

Even if the pitch of the sound leaving the source doesn't change,
you would still hear it increase if the source starts moving toward
you.  That's the so-called "Doppler effect".
3 0
3 years ago
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