an optician uses a plane mirror to help him. suppse a patient sits in a chair 2.5m away from him. He views the image of a chart which faces the mirror and is located 30m behindd him. how far is the chart as viewed by his eyes
Answer:
I think 75 m
Explanation:
tell if it was correct
a sample contains 110 g of a radioactive isotope. how much radioactive isotope will remain in the sample after 1 half-life?
a. 100g
b. 25 g
c. 75 g
d. 50 g
Answer:
The half-life of a radioactive isotope is the time such that the initial amount of the isotope is reduced to its half.
Thus, if we start with A grams of a given radioactive isotope, after a 1 half-life, we will have A/2 grams of the radioactive isotope.
In this case, we know that the sample has 110g of a radioactive isotope.
Then, after 1 half-life, we should have half of 110g, which is:
110g/2 = 55g
Then we should have 55 g of a radioactive isotope.
The answer that is closer to this result is option d (50 g), so that is the correct one.
How does the motion of the atoms in the spoon change when the spoon is placed in the hot coffee?
А
The atoms vibrate faster due to the conduction of heat through atoms in the spoon.
B
The atoms vibrate slower due to the conduction of heat through atoms in the spoon
С
The atoms move closer toward each other due to the radiation of heat through atoms in the spoon.
D
The atoms move away from each other due to the convection of heat through atoms in the spoon.
Answer:
A.The atoms vibrate faster due to the conduction of heat through atoms in the spoon.
A student uses 80 joules of energy to lift a backpack in a time of 0.75 seconds. How much power
does the student have?
Answer:
P = 106.7 W
Explanation:
Given that,
Work done in lifting a backpack, W = 80 J
It is lifted in 0.75 seconds
We need to find the power of the student. The power of an object is defined as work done per unit time. So,
[tex]P=\dfrac{W}{t}[/tex]
Put all the values,
[tex]P=\dfrac{80}{0.75}\\\\P=106.7\ W[/tex]
So, the power of the student is 106.7 W.
Which two parts do the capillaries surround?
A. small intestines and heart
B. heart and lungs
C. alveoli and small intestines
Answer:
do we have to choose 2 answers here?
Answer:
most probably it's C
Explanation:
alveoli is surrounded by capillaries and whit that option small intestines is also there
(c) Another spring has a spring constant of 250 N/m.
Calculate the work done in stretching the spring by 0.30 m.
State the unit.
Use the equation
E = 12 x K x x2
A(n) _______ studies physical components and characteristics of celestial objects.
The answer is ASTROPHYSICIST!
Answer:
Astronomers?
Explanation:
Answer:
Astrophysicist?
Explanation:
A car accelerates at a rate of 13m/s^2[S]. If the car's initial velocity is 120km/h[N]. What will its final velocity be in m/s, after two seconds.
Answer:
the final velocity of the car is 59.33 m/s [N]
Explanation:
Given;
acceleration of the car, a = 13 m/s²
initial velocity of the car, u = 120 km/h = 33.33 m/s
duration of the car motion, t = 2 s
The final velocity of the car in the same direction is calculated as follows;
v = u + at
where;
v is the final velocity of the car
v = 33.33 + (13 x 2)
v = 59.33 m/s [N]
Therefore, the final velocity of the car is 59.33 m/s [N]
For every 120 joules of energy input a car wastes 85 joules , find the useful energy output of the car ?
Answer:
35 Joules
Explanation:
Applying
Input Energy(Q) = Useful energy output(U)+Wasted Energy(W)
Q = U+W.............................. Equation 1
Make U the subject of the equation
U = Q-W................... Equation 2
From the question,
Given: Q = 120 Joules, W = 85 Joules
Substitute these values into equation 2
U = 120-85
U = 35 Joules
The upper layer of soil consisting of rock particles, water, air, and organic matter is the
Answer: Bedrock
Explanation:
Bedrock is the solid layer of rock beneath the soil. Soil is a mixture of rock particles, minerals, decayed organic material, air, and water. The decayed organic material in soil is humus, a dark-colored substance that forms as plant and animal remains decay.
Using the diagram above, the coefficient of kinetic friction for copper is ____ (Your answer should be given to the nearest thousandths.)
This coefficient _____ applies to all similar copper surfaces.
Answer:
μ= 0.0375, kinetic
Explanation:
For this exercise we set a reference system with the x axis parallel to the chord
Y axis
N - W = 0
N = W
X axis
T - fr = 0
the expression for the friction force is
fr = μ N
we substitute
T - μ W = 0
μ = T / W
we calculate
μ = 1.5 / 40
μ= 0.0375
coefficient of kinetic friction
Which of these scenarios describes circular motion?
es )
A)
The moon orbiting the Earth
B)
A cannonball flying from a cannon
C)
A car moving along a straight track
D)
The pendulum of a grandfather clock
A)
The moon orbiting the Earth
A bird is standing on an electric transmission line carrying a large amount of current. Find the power dissipated by the bird If the
current it experiences is 1.35^-10 A which results in a potential difference of .0054V.
Side Note:
(I know the answer is 7.3 x 10^-11 W, I just don’t know how to get it)
P = 7.3 × 10^-13 Watt
Explanation:
First of all, are you sure that what you have is the right answer?
Anyway, the definition of power dissipated is given by
P = I^2×R
where I is the current and R is the resistance. But we also know from Ohm's law that
V = IR
so we can rewrite the equation for power P as
P = I^2R = I(IR) = VI
= (0.0054 volt)(1.35 × 10^-10 A)
= 7.3 × 10^-13 Watt
A monochromatic beam of light has a frequency of 6.5 x 10" hertz. What color is the light?
O orange
O yellow
O violet
O blue
Answer:
violet
Explanation:
A baseball is thrown at a 22.5° angle and an initial velocity of 65 m/s. What will be its horizontal
and vertical velocity?*
Answer:
Horizontal
Explanation:
It is going more sideways than upwards
PLEASE ANSWER ASAP, WILL MARK BRAINLIEST***
Help please!!
What are the three criteria that determine if a wave is a sound wave?
Answer:
Wavelength, Amplitude, Time-Period, Frequency and Velocity or Speed.
Explanation:
Sound wave can be described by five characteristics: Wavelength, Amplitude, Time-Period, Frequency and Velocity or Speed. The minimum distance in which a sound wave repeats itself is called its wavelength. That is it is the length of one complete wave
Answer: Sound wave can be described by five characteristics: Wavelength, Amplitude, Time-Period, Frequency and Velocity or Speed.
Explanation:
The minimum distance in which a sound wave repeats itself is called its wavelength. That is it is the length of one complete wave.
If the temperature (at constant volume) of an ideal gas with 20 K is increased to 60 K, the pressure will be:
increased to 3P
increased to 40P
decreased by 3P
decreased by 40P
Answer:
it will obviously be decreased by 40p
What are successfulness of the Competition policy in South Africa?
Answer:
The product choices along with its competitive prices were provided to the consumers. Practices such as horizontal collusion and resale price maintenance was declared unlawful in 1984. Prevention of monopoly growth was the aim of the competition policy act.
Explanation:
hope this helps you
Help please, with #18, it’s a basketball question
Answer: D
Explanation:
Answer:
C. A lob pass.
Hope this helps!!
When will electric charges flow?
A. When the circuit is open.
B. When the circuit is incomplete.
C. When the circuit is closed.
D. When the switch is off.
Answer:
A
Explanation:
A projectile is launched from the ground with an initial velocity of 12ms at an angle of 30° above the horizontal. The projectile lands on a hill 7.5m away. The height at which the projectile lands is most nearly
A- 1.78m
B- 3.10m
C- 5.34m
D- 6.68m
E- 12.0m
Answer:
A. 1.78 m
Explanation:
Given;
initial velocity of the, u = 12 m/s
angle of projection, θ = 30°
the range of the projectile, R = 7.5 m
To obtain the height through which the projectile lands, we must calculate the maximum height reached by the projectile.
[tex]H = \frac{u^2\ sin^2\theta}{2g} \\\\H = \frac{(12)^2\times (sin(30))^2}{2 \times 9.8} \\\\H = \frac{144 \times (0.5)^2}{19.6} \\\\H = 1.84 \ m[/tex]
Therefore, the height is most nearly 1.78 m
What is the product of an oxidation reaction?
Ozone
Oxygen
Oxide
Answer:
Oxide
Explanation:
Ozone and oxygen are oxidising agents
[tex]O _{3} \: \: ozone \\ \\ O _{2} \: \: oxygen[/tex]
Answer:
Oxygen
Explanation:
The name oxidation actually originates from the word oxygen so the question answers it's self.
In case you don't know what oxidation is:
Oxidation occurs when an atom, molecule, or ion loses one or more electrons in a chemical reaction. When oxidation occurs, the oxidation state of the chemical species increases. Oxidation doesn't necessarily involve oxygen! Originally, the term was used when oxygen caused electron loss in a reaction.
Have a great day <3
Can anyone answer this its a science question NO LINKS!!!
Answer:
The correct answer is C I took the mastery test
Explanation:
Answer:
d last one
Explanation:
Tyra made the following bar graph shown to represent the relative distances of four different astronomical bodies from Earth.
The title of the bar graph is Distance of Bodies in Space from Earth. Four bars are labeled A, B, C, and D. Bar C is the shortest. Bar D is about three times the size of bar C. Bar A is about six times the size of bar C. Bar B is about eight times the size of bar C.
If D represents Mercury, which of the following could be represented by B and C?
B could be the moon, and C could be Venus.
B could be Venus, and C could be the moon.
B could be the moon, and C could be Jupiter.
B could be Jupiter, and C could be the moon.
Answer: D
Choice A calls B the moon which is incredibly tiny compared to Venus so this is wrong, choice B calls B Venus which is a relatively small planet and C the moon... that is a bit overkill so no. Choice C says B is the moon and C is Jupiter, Jupiter being the largest planet this is a easy no, leaving D to be the only logical and correct answer.
Explanation: MARK ME BRAINLIEST PLZZZZZZZZZZzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
Answer: Answer D. because B. Jupiter is the farthest from Earth from those answer choices and C. is the moon because it is the closest out of those answer choices.
So, the answer is D: B could be Jupiter, and C could be the moon.
Explanation: Please give Brainlist.
Hope this helps!!!!
See the picture and Anwser This
Answer:
20 m/s
Explanation:
Look at the time on the x-axis. Go up from 2 seconds until you reach a point. From that point go to the left and read from the y-axis.
A traveler at Newark airport pulls his 294N suitcase with constant velocity to the check-in counter applying a force of 159N at an angle of 37 degrees with the horizontal. Calculate the Normal force, frictional force and the coefficient of friction between the suitcase and the airport floor.
Answer:
N = 198.3 N, fr = 126.98 N and μ = 0.64
Explanation:
For this exercise we must use the translational equilibrium condition.
Let's set a reference system with the x-axis horizontally and the y-axis vertical. Let's use trigonometry to decompose the applied force
cos θ = Fₓ / F
sin θ = F_y / F
Fₓ = F cos θ
F_y = F sin θ
Fₓ = 159 cos 37 = 126.98 N
F_y = 159 sin 37 = 95.69 N
Y axis
N + F_y - W = 0
N = W - F_y
N = 294 - 95.69
N = 198.3 N
X axis
Fₓ -fr = 0
Fₓ = fr
fr = 126.98 N
the expression for the friction force is
fr = μ N
μ = fr / N
μ = 126.98 / 198.3
μ = 0.64
5 points
The figure below shows two people ice-skating. Person A collides with
person B. After the collision they move together with the same velocity.
Calculate the mass, m, of person B.
Before collision
After collision
Person A
mass = 60 kg
Person B
mass, m
Person A and person B
moving off together
Speed of
Person A -
5.5 m/s
Speed of
Person B -
2.0 m/s
Speed of Person A and
Person B = 4.0 m/s
mB = 45 kg
Explanation:
Using conservation of linear momentum,
mAvA + mbvB = (mA + mB)v
(60 kg)(5.5 m/s) + (2.0 m/s)mB = (60 kg + mB)(4.0 m/s)
(330) + 2mB = 240 + 4mB
2mB = 90
mB = 45 kg
Where was the first FIFA World Cup held?
(HINT: The host country won the tournament
Answer:
The 1930 FIFA World Cup was the inaugural FIFA World Cup, the world championship for men's national association football teams. It took place in Uruguay from 13 to 30 July 1930.
Explanation:
hope it helps if so pls give it the brainliest answer
Answer:
[tex]\huge\boxed{Uruguay\hookleftarrow}[/tex]
⎇ The first FIFA World Cup Championship took place in Uruguay from from 13 July 1930 to 30 July 1930.
Object A and Object B have the same volume of 10 cm³. Object A has a mass of 20 grams. Object B has a mass of 50 grams. Which object will have the greater density and why?
Answer:
Object B has greater density
desity A=20/10=2 g cm^-3 . density B=50/10=5 g cm^-3
the object that has greater mass has the greater density because the volume of the those two objects are same