Answer: 0.48g (A)
Explanation:
After each half life you have half the amount you had in the previous half life.
Since one half life takes 8 days, in 8 days one half life will take place
This means that the amount after 8 days will be half of what was there before
0.96/2 = 0.48g
If the half-life of iodine-131 is 8 days. If a sample originally contains 0.96 g of the isotope, then 0.48 g will remain after 8 days. The correct option is A.
Isotopes are variants of an element that have the same number of protons in their atomic nuclei but different numbers of neutrons. This means that isotopes of the same element have the same atomic number (which determines the element's identity) but different atomic masses.
Here in the question,
The half-life of iodine-131 is 8 days, which means that after 8 days, half of the original amount of iodine-131 will have decayed. We can use the following formula to calculate the amount remaining:
Amount remaining = Initial amount x (1/2)^(t/h)
Where t = the time elapsed
h = the half-life.
In this case, the initial amount is 0.96 g, the time elapsed is 8 days, and the half-life is also 8 days.
Now, we can plug in the values and solve for the amount remaining:
Amount remaining = 0.96 g x (1/2)^(8/8) = 0.48 g
Therefore, After 8 days, 0.48 g of iodine-131 will remain. The correct answer is A 0.48 g.
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You lift a 10-N physics book up in the air a distance of 1.0 m, at a constant velocity
of 0.50 m/s. What is the work done by gravity on the book?
1) +10 J
2) -10
3) +5.0
4) -5.0
The book is lifted upward, but gravity points down, so the work done by gravity must be negative (so you can eliminate options 1 and 3).
The force exerted on the book by gravity has magnitude
F = mg = (10 N) (9.80 m/s^2) = 9.8 N ≈ 10 N
You raise the book 1.0 m in the opposite direction, so the work done is
W = (10 N) (-1.0 m) = -10 J
The work done by gravity on the book is -10 Joules. The correct option is 2.
What is gravity?The force of attraction felt by a person at the center of a planet or Earth is called as the gravity.
Given are the three positions. The Earth has the acceleration due to gravity, g = 9.81 m/s²,
The book is lifted upward, but gravity points down, so the work done by gravity must be negative (so you can eliminate options 1 and 3).
The force exerted on the book by gravity has magnitude
F = mg = 10 N x( -9.80 m/s² )= -9.8 N
F ≈ -10 N
The book is raised by 1.0 m in the opposite direction, so the work done is
W =- 10 N x 1.0 m = -10 J
Thus, the correct option is 2.
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46) The rapid change of an electric field induces
A) a stronger electric field.
B) a magnetic field.
C) both of these
D) none of the above
Answer:
The answer is Option no. C because rapid changes can cause both magnetic field and stronger electric field
John and Caroline go out for a walk one day. This graph represents the distance they traveled over time.
During what part of thelr walk are they not moving?
A) From 0 to 0.75 hours
B)From 1.25 to 2.0 hours
From 0.75 to 1.25 hours
C) from 1.25 to 2.0 hours
D) they are moving the entire time
Answer:
From 0.75 to 1.25 hours
Explanation:
Given
See attachment for graph
Required
Point where they didn't move
This means that we identify the point where the distance didn't change.
Given that the distance is plotted on the y-axis, we simply check for the end points of any horizontal line on the graph
The horizontal line on the graph represents 30km and the time interval is: 0.75 to 1.25 hours.
Hence, (c) is correct
What are the magnitude and direction of a uniform electric field perpendicular to the ground that is able to suspend a particle of mass m = 1.30 g carrying a charge of +6.90 µC in midair, assuming gravity and the electrostatic force are the only forces exerted on the particle?
Answer:
the magnitude and direction of the uniform electric field is 1846.38 N/C and UPWARD respectively
Explanation:
Given the data in the question;
mass m = 1.30 g = 1.30 × 10⁻³ kg
Charge q = +6.90 µC = 6.90 × 10⁻⁶ C
we know that; g = 9.8 m/s
assuming gravity and the electrostatic force are the only forces exerted on the particle, hence the relation is;
F = mg and F = Eq
so
mg = Eq
make E subject of formula
E = mg / q
so we substitute
E = [ (1.30 × 10⁻³) × 9.8 ] / 6.90 × 10⁻⁶
E = 0.01274 / 6.90 × 10⁻⁶
E = 1846.38 N/C
Since the charge is positive ( + ), { direction is Upward }
Therefore, the magnitude and direction of the uniform electric field is 1846.38 N/C and UPWARD respectively
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Trace the flow of energy through the food pyramid, label the missing units of energy found at each level by calculating the change in energy
Answer:
Energy Flow
The chemical energy of food is the main source of energy required by all living organisms. This energy is transmitted to different trophic levels along the food chain. This energy flow is based on two different laws of thermodynamics:
First law of thermodynamics, that states that energy can neither be created nor destroyed, it can only change from one form to another.
Second law of thermodynamics, that states that as energy is transferred more and more of it is wasted.
Energy Flow in Ecosystem
The energy flow in the ecosystem is one of the major factors that support the survival of such a great number of organisms. For almost all organisms on earth, the primary source of energy is solar energy. It is amusing to find that we receive less than 50 per cent of the sun’s effective radiation on earth. When we say effective radiation, we mean the radiation, which can be used by plants to carry out photosynthesis.
Explanation:
Energy Flow in Ecosystem
The energy flow in the ecosystem is one of the major factors that support the survival of such a great number of organisms. For almost all organisms on earth, the primary source of energy is solar energy. It is amusing to find that we receive less than 50 per cent of the sun’s effective radiation on earth. When we say effective radiation, we mean the radiation, which can be used by plants to carry out photosynthesis.
Most of the sun’s radiation that falls on the earth is usually reflected back into space by the earth’s atmosphere. This effective radiation is termed as the Photosynthetically Active Radiation (PAR).
Overall, we receive about 40 to 50 percent of the energy having Photosynthetically Active Radiation and only around 2-10 percent of it is used by plants for the process of photosynthesis. Thus, this percent of PAR supports the entire world as plants are the producers in the ecosystem and all the other organisms are either directly or indirectly dependent on them for their survival.
The energy flow takes place via the food chain and food web. During the process of energy flow in the ecosystem, plants being the producers absorb sunlight with the help of the chloroplasts and a part of it is transformed into chemical energy in the process of photosynthesis.
This energy is stored in various organic products in the plants and passed on to the primary consumers in the food chain when the herbivores consume (primary consumers) the plants as food. Then conversion of chemical energy stored in plant products into kinetic energy occurs, degradation of energy will occur through its conversion into heat.
Then followed by the secondary consumers. When these herbivores are ingested by carnivores of the first order (secondary consumers) further degradation will occur. Finally, when tertiary consumers consume the carnivores, energy will again be degraded. Thus, the energy flow is unidirectional in nature.
Moreover, in a food chain, the energy flow follows the 10 percent law. According to this law, only 10 percent of energy is transferred from one trophic level to the other; rest is lost into the atmosphere. This is clearly explained in the following figure and is represented as an energy pyramid.
18 of 25
The practice of science can answer only scientific questions. And scientific
questions guide the design of investigations. What must be true of the
possible answers to a scientific question?
A. They agree with all prior experiments,
B. They can be supported by evidence,
C. They are popular with a majority of scientists,
D. They lead to increased funding of scientific research,
Answer:
B
Explanation:
Cause its true
find the equivalent resistance.
Answer:
Explanation:
Note the connection between D-L-H shorts out the resistors on the right. Those 4 resistors can be ignored.
The connection between D-L-K means the 2 resistors between C-D and C-K are in parallel. The equivalent resistance of 2 6-ohm resistors in parallel is 3 ohms.
Similarly the connection between K-L-H means the 2 resistors between J-K and J-H are in parallel. The equivalent resistance of 2 6-ohm resistors in parallel is 3 ohms.
Adding the resistors in series together:
A-C-L-J-D = 6 + 3 + 3 + 6
= 18 ohms
An 800-kHz radio signal is detected at a point 4.5 km distant from a transmitter tower. The electric field amplitude of the signal at that point is 0.63 V/m. Assume that the signal power is radiated uniformly in all directions and that radio waves incident upon the ground are completely absorbed. What is the magnetic field amplitude of the signal at that point
Answer:
[tex]B_2=2.1nT[/tex]
Explanation:
From the question we are told that:
Frequency [tex]F=800kHz[/tex]
Distance [tex]d=4.5km[/tex]
Electric field amplitude [tex]B_2=0.63V/m[/tex]
Generally the equation for momentum is mathematically given by
[tex]B=\frac{E}{C}[/tex]
Therefore
[tex]B_2=\frac{0.63}{3*10^8}[/tex]
[tex]B_2=0.21*10^{-8}[/tex]
[tex]B_2=2.1nT[/tex]
A proton accelerates from rest in a uniform electric field of 595 N/C. At one later moment, its speed is 1.15 Mm/s (nonrelativistic because v is much less than the speed of light). (a) Find the acceleration of the proton. (b) Over what time interval does the proton reach this speed? (c) How far does it move in this time interval? (d) What is its kinetic energy at the end of this interval?
200N force was used to move 150N block on an inclined plane of length 12m with a height of 4m. The efficiency of the inclined plane will be
Answer:
42.1%
Explanation:
Applying,
E(%) = (M.A/V.R)×100............. Equation 1
Where E(%) = Percentage efficiency, M.A = mechanical advantage, V.R = Velocity ratio.
But,
M.A = L/E............... Equation 2
Where L = Load, E = Effort.
From the question,
Given: L = 150 N, E = 200 N
Substitute these values into equation 2
M.A = 200/150
M.A = 1.33
Also,
V.R for Inclined plane = 1/sin∅ =
V.R = 1/sin∅............... Equation 2
Where ∅ = angle of the inclined plane.
Where,
tan∅ = 4/12
∅ = tan⁻¹(4/12)
∅ = 18.43°
Therefore,
V.R = 1/sin18.43
V.R = 3.16.
Substituting the value of M.A and V.R into equation 1
E(%) = (1.33/3.16)×100
E(%) = 42.1%
What is the current running through a parallel circuit containing a 10 V battery and three resistors, each 3 ohms
Answer:
the current through the circuit is 10 A.
Explanation:
Given;
voltage of the battery, V = 10 V
number of the parallel resistors, = 3
resistance of each resistor, r = 3 ohms
The equivalent resistance is calculated as;
[tex]\frac{1}{R_t} = \frac{1}{r_1}+ \frac{1}{r_2} + \frac{1}{r_3} \\\\\frac{1}{R_t} = \frac{1}{3}+ \frac{1}{3} + \frac{1}{3}\\\\\frac{1}{R_t} =\frac{3}{3} \\\\\frac{1}{R_t} = 1\\\\R_t = 1 \ ohms[/tex]
The current through the circuit is calculated as;
V = IRt
I = V/Rt
I = 10/1
I = 10 A
Therefore, the current through the circuit is 10 A.
A particle with charge q1 = +4.0 µC is located at x = 0, and a second particle with charge q2 = −2.1 µC is located at x = 15 cm. Determine the location of a third particle with charge q3 = +4.6 µC such that the net electric field at x = 25 cm is zero.
Answer:
x₃ = 0.0725 m
Explanation:
The force between the particles is electrical
F = [tex]k \frac{q_1q_2}{r_{12}^2}[/tex]
F = q₀ E_total
don q₀ is a positive test charge at the point of interest, therefore we can calculate the electric field at the point of interest x₀ = 0.25 cm
F = 0 → E_total = 0
E_total = E₁ + E₂ + E₃
E_total = [tex]k \frac{q_1}{r_{1o}^2} + k \frac{q_2}{r_{2o}^2} + k \frac{q_3}{r_{3o}^2}[/tex]
E_total = k ( [tex]\frac{q_1}{r_{1o}^2} + \frac{q_2}{r_{2o}^2} + \frac{q_3}{r_{3o}^2}[/tex] )
let's look for the distances
r₁₀ = (x₀ - 0)
r₁₀ = 0.25 m
r₂₀ = √(x₀ - x₂) ²
r₂₀ = √ (0.25 - 0.15) ²
r₂₀ = 0.10 m
r₃₀ = √ (0.25 - x₃) ²
we substitute
0 = 9 10⁹ (4 / 0.25² - 2.1 / 0.1² + 4.6 / (0.25-x₃)² )
4.6 / (0.25-x3)² = -4 / 0.25² + 2.1 / 0.1²
4.6 / (0.25-x3) ² = -146
(0.25 - x3) ² = - 4.6 / 146 = - 0.0315068
0.25 - x3 = 0.1775
x₃ = 0.25 - 0.1775
x₃ = 0.0725 m
Two blocks A and B with mA = 2.9 kg and mB = 0.87 kg are connected by a string of negligible mass. They rest on a frictionless horizontal surface. You pull on block A with a horizontal force of 6 N. Determine the tension in the string connecting the two blocks.
Answer:
Tension = 1.38 N
Explanation:
Given that:
Mass of block A [tex]m_A[/tex] = 2.9 kg
mass of block B [tex]m_B[/tex] = 0.87 kg
Force F = 6 N
Assume a = acceleration of the blocks.
Then:
[tex]m_A[/tex] (a) + [tex]m_B[/tex] (a) = 6
2.9a + 0.87a = 6
3.77a = 6
a = 6/3.77
a = 1.59 m/s²
Suppose T to be the tension in the string.
If we take a look at the forces acting on the first block, then:
F - T = [tex]m_A[/tex] (a)
T = F - [tex]m_A[/tex] (a)
T = 6 - 2.9(1.59)
T = 6 - 4.62
T = 1.38 N
a stone is thrown vertically upward with an initial velocity of 14m/sc negleting in air resistance find (a)Maximum height reached and (b)Time taken before it reached the ground
Answer:
1/2 m v^2 = m g H conservation of energy
H = (v^2 / (2 * g))^1/2 = (14^2 / 19.6)^1/2 = 10 m
H = 1/2 g t^2 time to fall 10 m
t = (2 * H / g)^1/2 = (20 / 9.8)^1/2 = 1.43 sec
Total time in air = 2 * 1.43 = 2.86
You can also use 2 a S = V0^2 since final velocity = 1.43 * 9.8 m/s = 14 m / s
and 2 a S = 2 * 9.8 * 10 = 196 m^2 / s^2 which is V0 squared
14. Name the 3 primary causes for the expected mass migration due to Climate
Change
Answer:
Climate change means a change in the state of the climate system that is sustained over a long period of time. These types of changes can occur due to natural or human causes.
Climate change and its effects on the planet can generate massive migrations, given the affectation of nature in certain parts of the planet.
Thus, an example would be the migration of populations from island countries, such as Fiji, Tonga or Samoa, to continental territories, due to the rise in sea level caused by the melting of the poles due to global warming.
Another example may be the desertification of certain regions, which would encourage migration by the inhabitants of these places to other territories.
Finally, climate change and its negative effects not only generate massive migrations caused by natural effects, but also by the economic effects of said changes, that is, by increases in poverty and inequality in the face of the scarcity of certain natural resources.
The gravitational force between two objects has a magnitude of F. If both masses were doubled and the distance between them doubled, the new force would have what magnitudes?
Answer:
F' = F
Explanation:
The gravitational force of attraction between two objects can be given by Newton's Gravitational Law as follows:
[tex]F = \frac{Gm_1m_2}{r^2}[/tex]
where,
F = Force of attraction
G = Universal gravitational costant
m₁ = mass of first object
m₂ = mass of second object
r = distance between objects
Now, if the masses and the distance between them is doubled:
[tex]F' = \frac{G(2m_1)(2m_2)}{(2r)^2}\\\\F' = \frac{Gm_1m_2}{r^2}[/tex]
F' = F
A car pulled by a tow truck has an acceleration of 2.0 m/s^2. What is the mass of the car if the net force on the car is 3,500 N?
Answer:
ans: 1750 kg
Explanation:
F = ma
so ,
m = F/a
= 3500 / 2
= 1750 kg
In an experiment, students measure the position x of a cart as a function of time t for a cart that starts at rest and moves with a constant acceleration. The following data are collected for the cart.
t(s) x(m)
0 0
1 4
2 16
3 36
4 64
The acceleration of the cart is most nearly:_____
Given :
Initial velocity , u = 0 m/s² .
To Find :
The acceleration of the cart.
Solution :
Since, acceleration is constant.
Using equation of motion :
[tex]x = ut + \dfrac{at^2}{2}\\\\x = \dfrac{at^2}{2}[/tex]
Putting, t = 1 s and x = 4 m in above equation, we get :
[tex]4 = \dfrac{a(1)^2}{2}\\\\a = 8 \ m/s^2[/tex]
Therefore, the acceleration of the cart is 8 m/s².
A volleyball is served at a speed of 8 / at an angle 35° above the horizontal. What is the speed of the ball when received by the opponent at the same height?
What do different forms of energy have in common?
A. They can push or pull on objects.
B. They give objects mass.
C. They can cause changes in matter.
d
D. They can cause objects to move.
Helllp meeee
A car with a mass of 850kg is moving at a speed of 72km/h when colliding with a concrete wall until it stops. After the collision, the car travels 2.0m before stopping. Determine the resultant of the forces acting on the car.
Answer:
Explanation:
The vehicle is experiencing a large force created by the concrete wall.
Equation
vf^2 = vi^2 + 2*a * d
Givens
vf = 0 The car eventually does stop.
vi = 72 km/hr * [ 1000 m/ km] * [1 hour / 3600 seconds]
vi = 20 meters / second
a = ?
m = 850 kg
Solution
vf^2 = vi^2 + 2a*d
0 = 20 m/s + 2* 2 *a
-20 m/s = 4a
-20/4 = a
a = - 5 m/s^2 The minus sign tells you the vehicle is slowing down. It sure should be.
Force = m * a
F = - 850 * (-5)
F = - 4250 N
The car provides a 4250 N force on it going east to west and a 4250 N force going from west to east provided by the concrete wall.
A toy plane weighing 1.5 kg is flying in the air at 8 m/s. The player
turns down its speed to 6m/s. What is the work done on it?
Use the work-energy theorem. The total work done on the plane is equal to the change in its kinetic energy:
W = ∆K
W = 1/2 (1.5 kg) (6 m/s)² - 1/2 (1.6 kg) (8 m/s)²
W = -21 J
(Note that the work must be negative since the "braking" force opposes the direction in which the plane is moving.)
A banked curve is designed for a roadway. The curve is designed so that a car traveling at 19.2 m/s can negotiate it without relying on the force of static friction. The radius of the curve is 51.2 in and the car has a mass of 2300 kg. a. What angle is the curve banked at (degrees)? b. What is the magnitude of the Normal force (N) between the road and the car when it is traveling at the designed speed? c. If a careless driver tries to negotiate the curve at a speed of 25 m/s ,will the direction of the frictional force be inward or outward?
A 50 Ω resistor in a circuit has a current flowing through it of 2.0 A. What is the power dissipated by the resistor?
A. 50 W
B. 200 W
C. 100 W
D. 25 W
Explanation:
A nichrome (ρ = 100x10-8 Ωm) wire has a diameter of 0.40 mm. ... A power line with a resistance of 2 ohms has a current of 80 A in it
1/8 Watt 50 kΩ resistor has 70 V applied.
A 50 Ω resistor in a circuit has a current flowing through it of 2.0 A then the power dissipated by the resistor is 200 Watt. Therefore the correct option is B.
What is power?The rate of doing work is known as power. The Si unit of power is the watt.
Power =work/time
The mathematical expression for the power is as follows
P = VI
where P is the power
V is the voltage
I is current passing through the circuit
The expression of power can be represented in many different forms by using the ohms law
As we know from Ohm's law that V= IR
Power = VI
by substituting V=IR in place of the voltage in power formula
P = I²R
As given in the problem a 50 Ω resistor in a circuit has a current flowing through it of 2.0 A so by substituting the values of the current and the resistance in the formula of power
P = 2²×50
= 200 Watt
Therefore the correct answer is B.
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In order to increase his gravitational potential energy by an amount equal to his kinetic energy at full speed, how high would such a sprinter need to climb
Answer:
Hola eres nuevo yo nací en el 2021 del 4 de junio37 microgram to Gigagram
3.7e-1437 Gigagram
BRAINILIEST PLEASE
Ples helppp meeeeee this is timedd
Answer:
50 km/h
Explanation:
From the graph, we can deduce the following parameters;
Distance = 20, 40, 60, 80, 100 km
Time = 0.5, 1.0, 1.5, 2.0 hours
To find the average velocity of the car over the first 2.00 hours.
First of all, we would determine the total distance and time.
Total distance = 20 + 40 + 60 + 80 + 100 = 300 km
Total time = 0.5 + 1.0 + 1.5 + 2.0 = 5
Average velocity = distance/time
Average velocity = 100/2
Average velocity = 50 km/h
A harmonic force of maximum value 25 N and frequency of 180 cycles>min acts on a machine of 25 kg mass. Design a support system for the machine (i.e., choose c, k) so that only 10% of the force applied to the machine is transmitted to the base supporting the machine.
Answer:
registrar y de h2rhrjlekeek tert2h2jwkwlwlwlwlwlwñlwk
21. The value of 'g on the surface of earth is 9.8 m/s. If mass of Jupiter is 319 times the mass of the
arth and its radius is 11 times the radius of the earth, find the value of 'g' on the surface of Jupiter.
What will be the weight of a man having mass 50 kg on the surface of Jupiter?
Vhy? Also write solve step by step
.
The answer is in the photo. Hope you are satisfied.Have a nice day ☺️
To solve this we must be knowing each and every concept related to acceleration due to gravity and its calculation. Therefore, the value of 'g' on the surface of Jupiter is 25.8m/s².
What is acceleration due to gravity?
Gravitational acceleration is indeed a vector, which implies it has a direction and a magnitude. The acceleration caused by gravity at the Earth's surface is denoted by the symbol g. It possesses a standard value of 9.80665 m/s².
Mathematically, the formula for acceleration due to gravity can be given as
g = G M /R²
G=6.674 x 10⁻¹¹ m³ kg⁻¹s⁻²
Mass of Jupiter=319×mass of earth
Radius of Jupiter=11×radius of earth
substituting all the given values in the above equation, we get
g = 6.674 x 10⁻¹¹× 319×6×10²⁴ /(11×6378 10³)²
On calculations, we get
g=25.8m/s²
Therefore, the value of 'g' on the surface of Jupiter is 25.8m/s².
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If a diffuse gas of atoms is trapped, cooled, and compressed, the de Broglie wavelengths of some atoms can become larger than the distance between atoms. The overlap between atoms leads to new states of matter. In one experiment, 87Rb atoms were cooled to 20 nK.
Required:
a. What is their de Broglie wavelength at this temperature?
b. How many times larger is this than the 0.47 nm diameter of the atoms?
Answer:
a) λ = 0.5346 10⁻⁹ m, b) 1.13
Explanation:
a) The wave-particle duality is
λ = [tex]\frac{\hbar }{p}[/tex]
the expression for energy kinetic is
E = p² / 2m
energy is also related to temperature
E = [tex]\frac{3}{2} \ kT[/tex]
we substitute
p =
λ =
Rubidium's mass is m = 85 uma
we calculate
λ =
λ=
λ = 0.5346 10⁻⁹ m
b) the relationship of the two lengths is
λ /0.47 nm = 0.53 / 0.47 = 1.13