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ser-zykov [4K]
3 years ago
12

Which force requires contact?

Physics
2 answers:
Minchanka [31]3 years ago
8 0

Answer:

A

Explanation: A is a example of Air resistance force, which is a contact force.

rosijanka [135]3 years ago
6 0
Answer is A. The force exerted by air as an object moves through it.
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Because melting point<span> and </span>freezing point<span> describe the</span>same<span> transition of matter, in this case from liquid to solid (</span>freezing) or equivalently, from solid to liquid (melting<span>).</span>
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12. Which of the following statements about
aliya0001 [1]
A seems to be correct
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2 years ago
A team of seven psychologist is study love, but each psychologist is working from a different perspective. In your opinion, what
stepladder [879]

Answer:

- Behavioral Psychologists

- Psychodynamic Psychologist

- Biological Psychologist

- Cognitive Psychologist

- Evolutionary Psychologist

- Socio - Cultural Psychologist

- Humanist Psychologist

Explained in explanation section

Explanation:

There are different classes of psychologists but for the purpose of this question we need just 7 that would fit into the study of love. These 7 will be;

1) A behavioral Psychologist might study behaviors associated with love, such as hugging, caressing or kissing.

2) A psychodynamic psychologist might study how a people's challenges with love are caused by unmindful and unresolved conflicts.

3) A biological psychologist might study which chemicals in the brain such as dopamine make people feel loved. He might also study parts of the what parts of the brain are active when people are in love.

4) A cognitive psychologist might study how people's cognitive processes will change when they are in love.

5) An evolutionary psychologist might study how certain actions or behaviors associated with love provided our forefathers with sufficient knowledge to handle their love problems.

6) A sociocultural psychologist might study how people express love in in various cultures across the world.

7) A humanistic psychologist might study the behavior of those who feel most loved and the impact it has in their lives

8 0
3 years ago
2. A rocket blasts off vertically from rest on the launch pad with a constant upward acceleration of 2.5 . At 30.0 s after blast
harina [27]

Answer:

a)The highest point reached by the rocket is 1412 m

b)The rocket crashes after 54.7 s

Explanation:

Hi there!

The equations of height and velocity of the rocket are the following:

h = h0 + v0 · t + 1/2 · a · t² (while the engines work).

h = h0 + v0 · t + 1/2 · g · t² (when the rocket is in free fall).

v = v0 + a · t (while the engines work).

v = v0 + g · t (when the rocket is in free fall).

Where:

h = height of the rocket at a time t.

h0 = initial height of the rocket.

v0 = initial velocity.

t = time.

a = acceleration due to the engines.

g = acceleration due to gravity (-9.8 m/s² considering the upward direction as positive).

v = velocity of the rocket at a time t.

First, let's find the velocity and height reached by the rocket until the engines fail:

h = h0 + v0 · t + 1/2 · a · t²

Let's set the origin of the frame of reference at the launching point so that h0 = 0. Since the rocket starts from rest, v0 = 0. So after 30.0 s the height of the rocket will be:

h = 1/2 · a · t²

h = 1/2 · 2.5 m/s² · (30.0 s)²

h = 1125 m

Now let's find the velocity of the rocket at t = 30.0 s:

v = v0 + a · t (v0 = 0)

v = 2.5 m/s² · 30.0 s

v = 75 m/s

After 30.0s the rocket will continue to ascend with a velocity of 75 m/s. This velocity will be gradually reduced due to the acceleration of gravity. When the velocity is zero, the rocket will start to fall. At that time, the rocket is at its maximum height. So, let's find the time at which the velocity of the rocket is zero:

v = v0 + g · t

0 = 75 m/s - 9.8 m/s² · t (v0 = 75 m/s because the rocket begins its free-fall motion with that velocity).

-75 m/s / -9.8 m/s² = t

t = 7.7 s

Now, let's find the height of the rocket 7.7 s after the engines fail:

h = h0 + v0 · t + 1/2 · g · t²

The rocket begins its free fall at a height of 1125 m and with a velocity 75 m/s, then, h0 = 1125 m and v0 = 75 m/s:

h = 1125 m + 75 m/s · 7.7 s - 1/2 · 9.8 m/s² · (7.7 s)²

h = 1412 m

The highest point reached by the rocket is 1412 m

b) Now, let's calculate how much time it takes the rocket to reach a height of zero (i.e. to crash) from a height of 1412 m.

h = h0 + v0 · t + 1/2 · g · t² (v0 = 0 because at the maximum height the velocity is zero)

0 = 1412 m - 1/2 · 9.8 m/s² · t²

-1412 m / -4.9 m/s² = t²

t = 17 s

The rocket goes up for 30.0 s with an acceleration of 2.5 m/s².

Then, it goes up for 7.7 s with an acceleration of -9.8 m/s².

Finally, the rocket falls for 17 s with an acceleration of -9.8 m/s²

The rocket crashes after (30.0 s + 7.7 s + 17 s) 54.7 s

6 0
3 years ago
Gravity is a force that pulls things
Katena32 [7]

Answer:

down and towards it

Explanation:

just because it is man

8 0
3 years ago
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