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dedylja [7]
3 years ago
13

A car accelerates from rest to 100 m/s in 20 s. What is its acceleration?

Physics
1 answer:
Dmitriy789 [7]3 years ago
7 0
  • initial velocity=0m/s=u
  • Final velocity=v=100m/s
  • Time=t=20s

\\ \sf\longmapsto Acceleration=\dfrac{v-u}{t}

\\ \sf\longmapsto Acceleration=\dfrac{100-0}{20}

\\ \sf\longmapsto Acceleration=\dfrac{100}{20}

\\ \sf\longmapsto Acceleration=5m/s^2

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Why was John Paul Jones's victory important in the war? His victory increased France's confidence in the skill of the Continenta
IRINA_888 [86]

Answer:

C. His victory against a superior British foe inspired the American troops.

Explanation:

John Paul Jones is considered the hero in the Revolutionary War. He is known as the Father of the US Navy.

In the Revolutionary War, Jones sided with the American colonists against the British and took hold of naval ships. In 1779, when the British warship <em>Serapis</em> was in conflict with the American warship <em>Bon Homme Richard, </em>Jones plugged the American warship with the Britisher's warship and tossed a grenade into the opponent warship. Thus when Jones was victorious in the war, this boosted the American spirits for the war.

Therefore, option C is the correct answer.

4 0
3 years ago
Read 2 more answers
Suppose you have two meter sticks, one made of steel and one made of invar (an alloy of iron and nickel), which are the same len
Mekhanik [1.2K]

Answer:

  • The difference in length for steel is 2.46 x 10⁻⁴ m
  • The difference in length for invar is 1.845 x 10⁻⁵ m

Explanation:

Given;

original length of steel, L₁ = 1.00 m

original length of invar, L₁ = 1.00 m

coefficients of volume expansion for steel, \gamma_{st.} =  3.6 × 10⁻⁵ /°C

coefficients of volume expansion for invar, \gamma_{in.} =  2.7 × 10⁻⁶ /°C

temperature rise in both meter stick, θ = 20.5°C

Difference in length, can be calculated as:

L₂ = L₁ (1 + αθ)

L₂  = L₁ + L₁αθ

L₂  - L₁ = L₁αθ

ΔL = L₁αθ

Where;

ΔL is difference in length

α is linear expansivity = \frac{\gamma}{3}

Difference in length, for steel at 20.5°C:

ΔL =  L₁αθ

Given;

L₁ = 1.00 m

θ = 20.5°C

\alpha = \frac{\gamma}{3} = \frac{3.6*10^{-5}}{3} = 1.2*10^{-5} /^oC

ΔL  = 1 x 1.2 x 10⁻⁵ x 20.5 = 2.46 x 10⁻⁴ m

Difference in length, for invar at 20.5°C:

ΔL =  L₁αθ

Given;

L₁ = 1.00 m

θ = 20.5°C

\alpha = \frac{\gamma}{3} = \frac{2.7*10^{-6}}{3} = 0.9*10^{-6}/^oC

ΔL  = 1 x 0.9 x 10⁻⁶ x 20.5 = 1.845 x 10⁻⁵ m

8 0
3 years ago
Which nuclei is not radioactive? <br> A. Am-241<br> B. Mg-24<br> C. Pu-241<br> D. U-238
Helen [10]

Hello!

Which nuclei is NOT radioactive?

A) Am-241 B) Mg-24 C) Pu-241 D) U-238

Solving:

It is noteworthy that chemical elements located on the periodic table in the lanthanide and actinide groups are radioactive.  

Am-241 (americium) belongs to the group of actinides and is a heavy and radioactive metal.  

Mg-24 (magnesium) is an essential element for the body, mainly for the nervous system, in addition to synthesizing proteins and serves for hormonal control, belongs to the group of alkaline earth metals and is a non-radioactive nucleus.

Pu-241 (plutonium) is an element that is isotope of fission by plutonium, belongs to the group of actinides and is a heavy and radioactive metal.  

U-238 (uranium) is an element that is isotope of non-fission uranium, belongs to the group of actinides and is a heavy and radioactive metal.

Answer:

B) Mg-24

_______________________

I Hope this helps, greetings ... Dexteright02! =)

6 0
3 years ago
A force causes a mass of 4 kg to have an acceleration of 8 m/s2. Suppose something causes the mass to be one-quarter of its orig
solniwko [45]

Explanation:

From Newton's second law:

F = ma

Given that m = 4 kg and a = 8 m/s²:

F = (4 kg) (8 m/s²)

F = 32 N

If m is reduced to 1 kg and F stays at 32 N:

32 N = (1 kg) a

a = 32 m/s²

So the acceleration increases by a factor of 4.

5 0
3 years ago
What is the purpose of the scapula to move during arm elevation?
Inessa [10]

The purpose of the scapula to move during arm elevation is increase the range of elevation of the arm.

<h3>What is the importance of movement of the scapula during arm elevation?</h3>

The scapula is an important bone which is found in the shoulder and back region of the body.

The scapula enables and increases the range of motion of the arm with its motions.

During arm elevation, the scapula undergoes an upward rotational motion.

Therefore, the  purpose of the scapula to move during arm elevation is increase the range of elevation of the arm.

Learn more about scapula motion at: brainly.com/question/5133017

#SPJ12

3 0
2 years ago
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