Answer:
50
Explanation:
A chemical symbol is to an element as a chemical formula is to a(n)
In positron-emission tomography (PET) used in medical research and diagnosis, compounds containing unstable nuclei that emit positrons are introduced into the brain, destined for a site of interest in the brain. When a positron is emitted, it goes only a short distance before coming nearly to rest. It forms a bound state with an electron, called "positronium", which is rather similar to a hydrogen atom. The binding energy of positronium is very small compared to the rest energy of an electron. After a short time the positron and electron annihilate. In the annihilation, the positron and the electron disappear, and all of their rest energy goes into two photons (particles of light) which have zero mass; all their energy is kinetic energy. These high energy photons, called "gamma rays", are emitted at nearly 180° to each other. What energy of gamma ray (in MeV, million electron volts) should each of the detectors be made sensitive to? (The mass of an electron or positron is 9 × 10-31 kg. 1 eV = 1.6 × 10-19 joules.
Answer:
Energy of gamma ray = 506250 eV
Explanation:
We are told that the mass of an electron or positron is 9 × 10-31 kg.
This means that their energies will be the same.
Thus; E_e = E_p
Now, since electron and positron annihilate to form gamma(γ) particle, then using work energy principle, we have;
E_γ + E_γ = E_e + E_p
Thus;
2E_γ = E_e + E_p
Since E_e = E_p, we now have;
2E_γ = 2E_e
Thus;
E_γ = E_e
Since all the energy of the electron is converted, then from Einstein's relativity theory, this implies that;
E_e = mc²
c is speed of light = 3 × 10^(8) m/s
And m is given as 9 × 10^(-31) kg
Thus;
E_e = 9 × 10^(-31) × (3 × 10^(8))^(2)
E_e = 810 × 10^(-16) J
Since E_γ = E_e
Thus;
E_γ = 810 × 10^(-16) J
We are given that; 1.6 × 10^(-19) J = 1eV
Thus; 810 × 10^(-16) J gives;
(810 × 10^(-16) × 1)/(1.6 × 10^(-19)) = 506250 eV
A man starts walking at a steady speed of 1 m/s and 6s later his son sets off from the same point in pursuit of him, starting at rest and accelerating at 2/3 m/s/s. How far do they go before they are together?
Answer:
The father will walk 6 more meters and the son will walk 12 meters
Explanation:
Uniform Speed and Acceleration
This is a problem where two objects have different types of motion. The father walks at a constant speed and later, his son starts a constant acceleration motion in pursuit of him.
Let's start with the father, whose speed is v=1 m/s during t=6 seconds. He travels a distance:
[tex]x=vt=1*6=6\ m[/tex]
Now the son, starting from rest (vo=0) accelerates at a=2/3 m/s^2. His speed will increase and eventually, he will catch up with his father. Let's suppose it happens at a time t1.
The distance traveled by the son is given by:
[tex]\displaystyle xs=v_o.t_1+\frac{a.t_1^2}{2}[/tex]
Since vo=0:
[tex]\displaystyle xs=\frac{a.t_1^2}{2}[/tex]
The father will continue with constant speed and travels a distance of:
[tex]xf=v.t_1[/tex]
For them to catch up, the distance of the son must be 6 m more than the distance of the father, because of the leading distance he has already taken. Thus:
[tex]xs=xf+6[/tex]
Substituting the equations of each man:
[tex]\displaystyle \frac{a.t_1^2}{2}=v.t_1+6[/tex]
We know a=2/3, v=1:
[tex]\displaystyle \frac{2}{3}\cdot\frac{t_1^2}{2}=t_1+6[/tex]
Simplifying:
[tex]\displaystyle \frac{t_1^2}{3}=t_1+6[/tex]
Multiply by 3:
[tex]t_1^2=3t_1+18[/tex]
Rearranging:
[tex]t_1^2-3t_1-18=0[/tex]
Factoring:
[tex](t_1-6)(t_1+3)=0[/tex]
Solving:
[tex]t_1=6 , t_1=-3[/tex]
Since time cannot be negative, the only valid solution is
[tex]t_1=6\ s[/tex]
The distance traveled by the son in 6 seconds is:
[tex]\displaystyle xs=\frac{2/3\cdot 6^2}{2}[/tex]
[tex]xs=12\ m[/tex]
Note the father will travel
[tex]xf=1*6=6\ m[/tex]
This 6 m plus the 6 m he was ahead of the son, make them meet while walking at 6 seconds.
Answer: The father will walk 6 more meters and the son will walk 12 meters
What are some things that can impact your mental health?
Wanda is afraid of gaining weight and putting herself at high risk for disease. she works out on a regular basis and eats right most of time. recently, Wanda some testing done. her BMI with some 17.2 and her waist circumference is 30 inches. what statement best describes next move for Wanda so she will be at the least risk for disease?
Answer:
C. Wanda's waist circumference indicates that she is not at risk, but her BMI indicates that she underweight. She should develop a plan to move her BMI into the normal range.
Explanation:
edge 2020 Brainliest would be appreciated
Answer:
Wanda's waist circumference indicates that she is not at risk, but her BMI indicates that she underweight. She should develop a plan to move her BMI into the normal range.
Explanation:
I just did the Cumulative Exam Review
Tension force ........... throughout a string that changes direction over a pulley.
(Fill in the blank)
Answer:
"is constant"
A car is traveling at a speed of 45 km/h into town. It takes the car 2 hours to get there. How far has the car traveled?
Answer:
90 km
Explanation:
45 km per hr
2 hrs
45 x 2 = 90
90 km/2 hrs
Hope this helps!
A car traveling at 30 m/s is brought to rest at a constant rate in 20 s by applying the brake. a) What is its acceleration? b) How far did it travel after the brake was applied?
Can air be forced into a smaller space? Explain with an example.
I will give out brainliest to person who has best answer☺️
Answer:
Yes. Yes, you can.
Explanation:
Combinations of increased pressure and decreased temperature force gases into containers that we use every day. You might have compressed air in a spray bottle or feel the carbon dioxide rush out of a can of soda. Those are both examples of gas forced into a smaller space at a greater pressure.
Hope this helps :)
On the surface of the earth the weight of an object is 200 lb. Determine the height of the
object above the surface of the earth, in miles, for the object to register a weight of 125
pounds.
Answer:
The height of the object is 5007.4 miles.
Explanation:
Given that,
Weight of object = 200 lb
We need to calculate the value of [tex]Gmm_{e}[/tex]
Using formula of gravitational force
[tex]F=\dfrac{Gmm_{e}}{r^2}[/tex]
Put the value into the formula
[tex]200=\dfrac{Gmm_{e}}{(3958.756)^2}[/tex]
[tex]200\times(3958.756)^2=Gmm_{e}[/tex]
[tex]Gmm_{e}=3.134\times10^{9}[/tex]
We need to calculate the height of the object
Using formula of gravitational force
[tex]F=\dfrac{Gmm_{e}}{r^2}[/tex]
Put the value into the formula
[tex]125=\dfrac{200\times(3958.756)^2}{r^2}[/tex]
[tex]r^2=\dfrac{200\times(3958.756)^2}{125}[/tex]
[tex]r^2=25074798.5[/tex]
[tex]r=\sqrt{25074798.5}[/tex]
[tex]r=5007.4\ miles[/tex]
Hence. The height of the object is 5007.4 miles.
leaves uses_,_and_to make food for the plant
light, water, carbon dioxide
Explanation:
c02 , h20 and light
We can compare these two interactions on the basis of impulse (see above), but sometimes, we are more interested in the forces (human body can withstand very large amount of impulse, if it's delivered over a long time with small forces, but we cannot withstand very large forces lasting over more than a few milliseconds, delivering relatively small impulse). In order to estimate average force from impulse, we need the duration of interaction. Suppose that the contact of the bat with the baseball in (b) lasts for 0.7 milliseconds. What is the magnitude of the average force that the bat exerts on the baseball, for the duration of contact
Complete Question
The complete question is shown on the first uploaded image
Answer:
a
[tex]I = 476 \ N \cdot s [/tex]
b
[tex]I_1 = 14.21 \ N\cdot s [/tex]
c
[tex]F = 20300 \ N [/tex]
Explanation:
Considering the first question
From the question we are told that
The force produced is [tex]F = 3400 \ N[/tex]
The duration of the punch is [tex]t = 0.14 \ s[/tex]
Generally the impulse delivered is mathematically represented as
[tex]I = F * t[/tex]
=> [tex]I = 3400 * 0.14[/tex]
=> [tex]I = 476 \ N \cdot s [/tex]
Considering the second question
The approaching velocity of the ball is [tex]v_b = 45 \ m/s[/tex]
The leaving velocity of the ball is [tex]v_l = -53 \ m/s[/tex]
The mass of the ball is [tex]m_b = 0.145 \ kg[/tex]
Generally the magnitude of the impulse delivered is mathematically represented as
[tex]I_1 = m* v_b - m * v_l[/tex]
=> [tex]I_1 = [0.145 * 45] - [0.145 * -53][/tex]
=> [tex]I_1 = 14.21 \ N\cdot s [/tex]
Considering the third question
The duration of the impact of the bat is [tex]t _1 = 0.7 \ ms = 0.7 *10^{-3} \ s[/tex]
Generally the average force exerted by the bat is mathematically represented as
[tex]F = \frac{I_1}{t_1}[/tex]
=> [tex]F = \frac{14.21 }{0.7 *10^{-3}}[/tex]
=> [tex]F = 20300 \ N [/tex]
which one is the biggest unit of plane angle
radian degree or revolution
Answer:
i think radian degree thank you
Explanation:
cuz right the degree angle i responsible more
Answer:
Its radian degree
Explanation:
Because the length of an arc of a unit circle is equal to measurement in radians of angle.
So it is the biggest unit of plane angle
A tennis ball is released from a height of 2.0 m above the floor, and then bounces three times. With each bounce, dissipative forces cause it to lose 16.0% of its mechanical energy. How high does it reach after the third bounce?
140 cm
120 cm
120 mm
12 cm
Answer:
12 cm
Explanation:
From what I got with my answer (8.192 cm) I went ahead and rounded it to the closest answer which is 12 cm. Hopefully im correct but if not, I apologize in advance.
5
2. When you keep the mass the same and decrease the unbalanced force how does the acceleration change?
Answer:
The acceleration will decrease due to less force acting on the object.
Explanation:
Will give brainliest!!!!! Help asap
Answer:
Correct choice: 5,400 Km/h
Explanation:
Unit Conversions
We'll use the following conversions:
1 Km = 1,000 m
1 h = 3,600 s
Convert the speed of sound in water (1.5\cdot 10^3\ m/s) to Km/h:
[tex]\displaystyle 1.5\cdot 10^3\ m/s*\frac{ 3,600\ s/h}{ 1000 \ Km/m}[/tex]
[tex]=5,400\ Km/h[/tex]
Correct choice: 5,400 Km/h
is 4x a term? or does it have to remove the 4 to be a term
Answer:
4x is a term oonly
No need to be romoved
URGENT!! A 0.057 kg tennis ball and a tennis racket collide. The racket has an initial
momentum of -2.80 kg m/s and a final momentum of -1.97 kg-m/s. The ball
has an initial momentum of 0.02565 kg-m/s. If you assume the collision is
elastic, what is the final velocity of the ball?
O A. -83.26 m/s
O B. -0.80 m/s
O C. -14.11 m/s
O D. -4.75 m/s
Answer:
-14.11
Explanation:
PLEASE HELP
Question 4 of 10
Which statement is true of a piece of ice at 0°C that is put into a freezer at
-18°C?
A. The ice cube will remain unchanged.
B. The ice cube will gain mass from the surroundings.
C. The ice cube will lose thermal energy to the surroundings.
D. The ice cube will gain thermal energy from the surroundings.
The ice cube will lose thermal energy to the surroundings. The given statement is true of a piece of ice at 0°C that is put into a freezer at -18°C. Thus, the correct option is C.
What is thermal energy?The term thermal energy is used loosely in various different contexts in physics and engineering mainly. Thermal energy can refer to several different well-defined physical concepts. These concepts include the internal energy or the enthalpy of a body of matter and the radiation energy, the heat energy, which is defined as a type of energy transfer and it is the characteristic energy of a degree of freedom.
If a piece of ice at 0°C that is put into a freezer at -18°C then it can be said that the ice cube will lose thermal energy to the surroundings.
Therefore, the correct option is C.
Learn more about Thermal energy here:
https://brainly.com/question/18989562
#SPJ2
Types of muscle tissue includes
Skeletal muscle
Cardiac muscle
Smooth muscle
All of the above
Answer:
D. all of the above
Explanation:
hope it helps
Do 2. A cyclist starts from rest and accelerates along a straight path to a speed of
12.15 m/s in a time of 4.5 seconds.
What is the cyclist's acceleration to the nearest tenth?
O
54.7 m/s2
o
24.3 m/s?
2.7 m/s2
De
3.4 m/s?
The cyclist's acceleration to the nearest tenth is: C. 2.7 [tex]m/s^2[/tex].
Given the following data:
Initial velocity = 0 m/s (since the cyclist starts from rest).Final velocity = 12.5 m/s.Time = 4.5 seconds.To find the cyclist's acceleration to the nearest tenth:
Acceleration is calculated by subtracting the initial velocity from the final velocity and dividing by the time.
Mathematically, acceleration is given by the formula;
[tex]A = \frac{V - U}{t}[/tex]
Where:
A is the acceleration.V is the final velocity.U is the initial velocity.t is the time measured in seconds.Substituting the given parameters into the formula, we have;
[tex]A = \frac{12.5\; - \;0}{4.5} \\\\A = \frac{12.5}{4.5}[/tex]
Acceleration, A = 2.7 [tex]m/s^2[/tex]
Therefore, the cyclist's acceleration to the nearest tenth is 2.7 [tex]m/s^2[/tex].
Read more: https://brainly.com/question/8898885
Oil is a powerful source of energy used for cars, machines, and many other purposes. While studying sources of energy that could replace the use of oil, a student thinks about solar power, wind power, nuclear power, and electric batteries. The students asks, "Which type of source will waste the least energy and provide the most energy in all situations?" Which best describes why a scientist would ask a different question than this one?
The question asks about subjective personal preferences regarding energy.
The question focuses on the objective measurements of amounts of energy.
The question has too wide of a focus, as though all situations can be studied at once.
The question is focused on the future and finding new answers about changing needs.
Answer:
The question has too wide of a focus, as though all situations can be studied at once
Explanation:
I took the test
Answer:
The question has too wide of a focus, as though all situations can be studied at once
Explanation:
i took ed test
Work occurs when (2 points) an applied force results in movement of an object in the same direction as the applied force an object is subjected to balanced forces resulting in movement of the object the energy present is the result of the force acting on the object the movement of the object was caused by a force and is in the opposite direction of the force
Answer:
.
Explanation:
what happends when you slowly pull out the paper while theirs a coin on top
A motorcycle is stopped at a stop light. When the light turns green it
accelerates at 4.2 m/s^2. How far does it travel during 3 s? *
Answer: 18.9 m
Explanation:
i did the kinematic equation & found the answer.
I WILL MARK YOU AS BRAINLIEST IF RIGHT
In order to climb up a mountainside, a train needs to start at a speed of 40 mph. The speed limit on the track, however, is 25 mph. How much time does the train need to get up to 40 mph if it can accelerate 4 mph per minute ?
Let's see what to do buddy.....
_________________________________
[tex]Acceleration = 4 \: \: \frac{mile}{ h } p( min ) [/tex]
Thus ;
The speed increases 4 units per minute.
The train has a speed of 25 mph now.
After a minute it has a speed of 29 mph.
After a minute it has a speed of 33 mph.
After a minute it has a speed of 37 mph.
Look ; 4 units per minute means 4 units per 60 seconds, thus the speed increases 1 unit per 15 seconds .
If the speed wants to increasing from 37 to 40 , needs 3 × 15 seconds = 45 sec.
So we have : 1 min + 1 min + 1 min + 45 sec .
3 minutes and 45 seconds or 225 seconds need to the speed increasing from 25 mph to 40 mph.
_________________________________
And we're done.....♥️♥️♥️♥️♥️
Two cars traveling in the same direction pass you at exactly the same time . The car that is going faster
moves farther in the same amount of time.
Explanation:
based on my answer......
we supposed to assume that both cars are equal except for speed. So they would have the same mass.....
Anyway, the question doesn't tell you anything about weight or size, so you can't tell from the information given which has more mass.
But the very definition of 'faster' is 'moves farther in the same amount of time'.
Hope this helps
Answer:
They both moves at the same speed
Explanation:
hope it works
3. A substance has a density of 19.3 g/ml. What is the volume of 20.2 g of the
substance? Hint: density can be used as a conversions factor
Answer:
The answer is 1.05 mLExplanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} \\ [/tex]
From the question we have
[tex]volume = \frac{20.2}{19.3} \\ = 1.04663212...[/tex]
We have the final answer as
1.05 mLHope this helps you
Explain why the interconnection is not valid. Explain why the interconnection is not valid. A valid interconnection would require the 3 AA and 4 AA sources to supply different currents in the same direction, which they do not. A valid interconnection would require the 3 AA and 4 AA sources to supply different currents in opposite directions, which they do not. A valid interconnection would require the 3 AA and 4 AA sources to supply the same current in opposite directions, which they do not. A valid interconnection would require the 3 AA and 4 AA sources to supply the same current in the same direction, which they do not.
Complete Question
The diagram for this question is shown on the first uploaded image
Explain why the interconnection is not valid.
i A valid interconnection would require the 3 A and 4 A sources to supply different currents in the same direction, which they do not.
ii A valid interconnection would require the 3 A and 4 A sources to supply different currents in opposite directions, which they do not.
iii A valid interconnection would require the 3 A and 4 A sources to supply the same current in opposite directions, which they do not.
iv A valid interconnection would require the 3 A and 4 A sources to supply the same current in the same direction, which they do not
Answer:
The correct option is iv
Explanation:
Looking at the diagram we see that the current source are connected in series, generally the current flowing through two source that are connected in series is suppose to be the same but in this case it is not so
i.e [tex]4A \ne 3 A[/tex] hence Kirchhoff's law is broken or not followed in this circuit which means the interconnection is not valid
also another reason why the interconnection is not valid is because the current are flowing in the different directions
If you had a 30 pound barbell at home and you wanted to compare your muscular endurance to your younger brother's which method would be the best to use.
Answer:A
Explanation:
Absolute method
Answer:
absolute method
Explanation:
trust
