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Yuliya22 [10]
3 years ago
13

Friends tell you that on a recent trip their average velocity was +20 m/s. Is it possible that at any time during their trip the

ir velocity was -20 m/s? Explain, and give an example to justify your answer. PLEASE HELP
Physics
1 answer:
xz_007 [3.2K]3 years ago
4 0

Answer: Yes. Please find the answer in the explanation.

Explanation:

Yes. Since velocity is a vector quantity, that is, it has both magnitude and direction.

If the displacements covered are not of the same direction, the velocity will not also of the same direction.

Take for instance, if the velocity in a positive is 40 m/s and velocity in the opposite direction is - 20 m/s . Then, the resultant velocity will be 40 - 20 = 20 m/s

Therefore,  it is possible that at any time during their trip their velocity was -20 m/s.

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The process by which the gene in the nucleotide suddenly changes its position is called.
Ksenya-84 [330]

Mutation is the process by which the gene in the nucleotide suddenly changes its position

Any change in the structure of a gen or in the usual DNA sequence of a cell is called mutation. It can be caused by mistakes during cell division when the DNA is copied or by the exposure to DNA damaging agents in the environment like UV light or cigarette smoke, and may be transmitted to subsequent generations.

A mutation is a permanent alteration of the nucleotide sequence of an organism, virus or other genetic elements.

There are three types of mutations:

  • Base substitutions
  • Deletions
  • Insertions

<h3>What is DNA?</h3>

The Deoxyribonucleic acid, also called DNA, is the hereditary material that carries genetic information for the development and functioning of humans and almost all other organisms. DNA is made of nucleotides.

Learn more about DNA at brainly.com/question/16099437

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8 0
2 years ago
9. Carlos jumps out of a hovering helicopter. After he opens his parachute, his acceleration due to gravity decreases
nata0808 [166]

Answer:

A The force of air resistance becomes equal in magnitude to his weight.

Explanation:

When Carlos jumped out of the helicopter, he fell with a downward force which is proportional to his weight.

His weight is the product of his mass and acceleration due to gravity.

When the parachute is deployed, air resistance between the air molecules and the surface area of the parachute generates a drag force, which acts upwards.

If the drag forces exceeds his weight, then his net force will be directed upwards.

If his weight exceeds the drag forces, then the net force on his body will be downwards.

In the case that his drag force, and his weight are equal, there will be a zero net force on him, and he will experience no acceleration.

So, if after he opens his parachute, his acceleration due to gravity decreases  to zero, then we can say that this is because  the force of air resistance (drag) becomes equal in magnitude to his weight.

5 0
4 years ago
A 1 m long wire of diameter 1mm is submerged in an oil bath of temperature 25-degC. The wire has an electrical resistance per un
Zarrin [17]

Answer:

steady state temperature =88.7deg C

t=time within  1 deg C of it steady state is 8.31s

Explanation:

A 1 m long wire of diameter 1mm is submerged in an oil bath of temperature 25-degC. The wire has an electrical resistance per unit length of 0.01 Ω/m. If a current of 100 A flows through the wire and the convection coefficient is 500W/m2K, what is the steady state temperature of the wire? From the time the current is applied, how long does it take for the wire to reach a temperature within 1-degC of the steady state value? The density of the wire is 8,000kg/m3, its heat capacity is 500 J/kgK and its thermal condu

The diameter of the wire is known to be=1mm

properties=

The density of the wire is 8,000 kg/m3,

heat capacity is 500 J/kgK

themal conductivity is 20W/m.K

electrical resistance per unit length of 0.01 Ω/m

from lump capavity method

B_{i} =\frac{hr/2}{k}

500*(2.5*10^-4)/20

0.006<0.1

we know also, to find steady state temperature

\piDh(T-Tinf)=I^{2} R_{e}

make T the subject of the equation , we have

T=25+\frac{100^2*0.01}{\pi*0.001*500 }

T=88.7 degC

rate of chnage in temperature

dT/dt=\frac{I^2*Re}{rho*c*\pi*D^2/4 } -\frac{4h}{rho*c*D} (T-Tinf)

at t=o and integrating both sides\frac{T-Tinf-(I^2*Re/\pi*Dh) }{Ti-Tinf-(I^2*Re/\pi*Dh } =exp\frac{-4ht}{rho*c*D}

we have

\frac{87.7-25-63.7}{25-25-63.7} =exp\frac{4*500t}{8000*500*0.001}

t=8.31s

steady state temperature =88.7deg C

t=time within  1 degC of it steady stae is 8.31s

7 0
3 years ago
An aneurism refers to?
Alona [7]

Answer:

The correct answer is a blocked blood vessel.

Explanation:

Hope this helped Mark BRAINLIEST!!!

4 0
3 years ago
If Jim could drive a Jetson's flying car at a constant speed of 440 km/hr across oceans and space, approximately how long (in mi
Makovka662 [10]

Answer:

t = 2.94 x 10⁶ years

Explanation:

The equation used in the case of constant speed is:

s = vt

t = s/v

where,

s = distance = 12 light years

s = (12 light years)(9.461 x 10¹² km/light year) =  113.532 x 10¹² km

v = speed = 440 km/hr

t = time passed = ?

Therefore,

t = (113.532 x 10¹² km)/(440 km/hr)

t = 2.58 x 10¹¹ hr

Now, converting it to years:

t = (2.58 x 10¹¹ hr)(1 year/8766 hr)

t = 2.94 x 10⁶ years

8 0
4 years ago
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