Answer:
d
Explanation:
The half-life of cobalt-60 is 5.26 years. If 50 grams are left after 15.78 years, how many grams were in the original sample?
Answer:
Explanation:
Half life = 5.6
no of half life in 15.78 years = 15.78 / 5.26
= 3 .
[tex]N = N_0(\frac{1}{2})^n[/tex]
N₀ is original mass , N is mass after n number of half lives.
Inserting the given data in the equation above
[tex]50 = N_0(\frac{1}{2})^3[/tex]
N₀ = 50 x 2³
= 400 gm .
original sample will contain 400 gms of sample.
Kinetic friction is the frictional force needed to start an object at rest into
motion.
A. True
B. False
Answer:
b.false i think
Explanation:
i hope i am correct and helps you
Answer:false
Explanation:
I just did it
which has a greater kinetic energy, a bowling ball that has a mass of 5kg travelling at 6m/s, or a ship that has a mass of 120000kg and is moving at 0.02m/s?
Answer:bowling ball has greater kinetic energy
Explanation:
Kinetic energy of bowling ball:
mass=m=5kg
Velocity=v=6m/s
Kinetic energy =ke
Ke=0.5 x m x v x v
Ke=0.5 x 5 x 6 x 6
Ke=90J
Kinetic energy of ship:
mass=m=120000kg
velocity=v=0.02m/s
Ke=0.5 x m x v x v
Ke=0.5 x 120000 x 0.02 x 0.02
Ke=24J
The bowling ball has greater kinetic energy than the ship.
What is kinetic energy?The kinetic energy of an object is the work an object can do by its motion. Kinetic energy is a scalar quantity as it does have magnitude only.
When work is done, energy is transferred, and the object moves at a new speed. The energy is transferred kinetic energy, which depends on the mass and speed.
The SI unit of kinetic energy is Joule and the CGS unit of kinetic energy is erg. The expression of kinetic energy that is used to calculate it is:
K.E. = (1/2) mv²
The mass and the velocity of the bowling ball are 5 Kg and 6 m/s respectively.
The kinetic energy of the bowling ball = (1/2) × 5× (6)² = 90 J
The mass and the velocity of the ship are 120000 Kg and 0.02 m/s respectively.
The kinetic energy of the bowling ball = (1/2) × 120000× (0.02)² = 24 J
Therefore, the kinetic energy of the bowling ball is greater than the ship.
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A 1500kg car moves foward with 30kg•m/s of momentum. What is its velocity
Select one
•-1470m/s
•0.02m/s
•45,000m/s
•-50m/s
Answer:
v = 30 /1500= 0.02 m/s
................
To hear a train approaching from far away, why is it more convenient to put the ear to the track?
Answer:
If you want to hear a train approaching from far away,it is more convenient to put the ear to the track.This is because sound can travel through railway track (solid ) faster than through air.
What causes atoms to bond together
?!?
Answer:
electrostatic attraction
Explanation:
Atoms form chemical bonds with other atoms when there's an electrostatic attraction between them. This attraction results from the properties and characteristics of the atoms' outermost electrons, which are known as valence electrons.
What is true of a match burned in a closed system?
Answer:
The match is made of wood or paper, mainly cellulose, a carbohydrate. When it burns, carbon and hydrogen combine with oxygen in the air and go off into the atmosphere. The match loses mass, but the mass goes somewhere else—in this case, the atmosphere. When a match burns, its mass decreases
Explanation:
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A man can lift a mass of 200kg onThe surface of the earth. what is the amount of mass he can lift on the surface of the moon?
Answer:
1,211.1 kg.
Explanation:
the force of gravity is less on the moon than on earth, so if the man can lift 200kg on earth, he could lift a greater amount on the moon because there is less resistance from gravity.
To know the amount of mass he can lift on the moon, we first need to know the amount of weight that is equivalent to those 200kg here on earth. This because the weight of the object is equal to the force that must be applied to lift it, and that force is applied by the man and it will be the same here and on the moon.
We calculate weight using the formula:
[tex]w=mg[/tex]
where [tex]w[/tex] is the weight of the object (the force with which the earth attracts the object) [tex]m[/tex] is the mass and g the acceleration of gravity.
so
[tex]w=200g[/tex]
for earth the acceleration due to gravity is: [tex]g=9.81m/s^2[/tex]
thus:
[tex]w=(200kg)(9.81m/s^2)\\w=1962N[/tex]
now we use this value to calculate the mass he can lift on the moon, since for the moon [tex]g=1.62m/s^2[/tex].
we use the same equation, w =mg substituting w = 1962N and [tex]g=1.62m/s^2[/tex]:
[tex]w=mg\\\\1962N=m(1.62m/s^2)\\\\m=\frac{1962N}{1.62m/s^2}\\\\ m=1,211.1kg[/tex]
he can lift 1,211.1 kg.
You can also find the result using the approximate value of the acceleration of gravity on the moon as g/6, where g is the acceleration on earth.
Only the sun and other stars in space generate these kinds of waves:
Answer:
Ultraviolet Waves.Explanation:
The Sun emits waves called "Solar Waves", which have a wavelengths between 160 and 400 nanometers. According to the electromagnetic spectrum, these waves are defined as Ultraviolet, which have a frequency around the order of [tex]10^{16}[/tex], which is really intense and high energy.
Therefore, the answer is Ultraviolet Waves.
2. A new racecar track is being created, and the owners want the cars to complete 10
miles in 7 laps. What does the diameter of the track have to be to meet their
requirements?
Answer:
0.45 miles
Explanation:
since, car will be running on the edge of track, distance covered in one lap by car will be equal to circumference of track.\
we will use value of pi as 22/7
Circumference for any circular shape is given by [tex]\piD[/tex][tex]\pi D[/tex]
Hence, in one lap [tex]\pi D[/tex] distance will be covered
in 7 laps [tex]7 \pi D[/tex] distance will be covered.
but is given that 7 laps should be equal to 10 miles
so 10 miles will be equal to [tex]7\pi D[/tex]
[tex]7\pi D= 10 \ miles\\=> 7*(22/7)* D= 10 \ miles\\=> 22D = 10 \ miles\\=> D = 10/22 \ miles\\=> D = 0.45 \ miles[/tex]
Thus, diameter of track will be 0.45 miles to meet the requirement.
a man is trying to move a piano by himself, but it will not move, what force must they overcome to start the piano moving?
Answer:
The friction of the piano and the weight
Explanation:
Explain why beaches can be considered both erosional and depositional. Remember to write in complete sentences!
Answer:
Waves wash against the shore which can lead to erosion. However, the waves also bring in pebbles and sand particles from the ocean, which is an example of deposition.
Explanation:
That would be my answer
Jenny and Fred both play a long note on their trombones. A stationary observer hears the sound increasing and decreasing repeatedly in loudness. Which of these must be true?
A.The sound waves from the two trombones have slightly different frequencies.
B. The sound waves from the two trombones have the same frequency.
C. The sound waves from the two trombones have slightly different amplitudes.
D. The sound waves from the two trombones have the same wavelength.
E. The sound waves from the two trombones have slightly different velocities.
Answer:
A.The sound waves from the two trombones have slightly different frequencies.
Explanation:
This is because, a difference in frequency of waves from two different sources would result in either constructive or destructive interference of the waves. Thereby, causing the observer to hear the sound increasing or decreasing.
Answer:
A.The sound waves from the two trombones have slightly different frequencies.
In a step down transformer, voltage steps down. What factor must go up?
Answer:
A transformer that increases the voltage from primary to secondary (more secondary winding turns than primary winding turns) is called a step-up transformer. Conversely, a transformer designed to do just the opposite is called a step-down transformer.
Explanation:
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How are the electric field lines around a positive charge affected when a second positive charge is near it?
Answer:Because it likes to repel and attract opposites
Which structure connects muscles to bone?
Answer: tendons connect muscles to bones
Explanation:
Which of the following are two factors that determine speed?
a. acceleration and time
b. distance and time
c. velocity and time
d. motion and time
Answer:
B) Distance and Time
Explanation:
Equation for speed: S = D / T
Speed equals the distance you traveled divided by the amount of time it took to get to that destination.
The two factors which are required to determine the speed of a object are distance traveled by it and time taken by it.
What is speed?The speed is the rate at which the total distance by a object is traveled in the time taken.
Speed of a object can be given as,
[tex]s=\dfrac{d}{t}[/tex]
Here, (d) is the distance traveled by the object and (t) is time taken but the object to cover that distance.
As the unit of the distance is measured in the meter and the time measure in the second. Thus the speed of a object is measured in the meter per second.
In the vehicles the speed of vehicle is also measured in the kilometre per hour or miles per hour.
Hence, the two factors which are required to determine the speed of a object are distance traveled by it and time taken by it.
Thus the option B is the correct option.
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what is the function of strong nuclear forces
Answer:
The strong force binds quarks together in clusters to make more-familiar subatomic particles, such as protons and neutrons. It also holds together the atomic nucleus and underlies interactions between all particles containing quarks
Explanation:
PLEASE GIVE ME BRAINLIEST IF NEW IT SHOULD SAY MARK AS BRAINLIEST IF NOT YOULL HAVE TO WAIT A DAY AND BRAINLY WILL REMIND YOU
The life cycle of stars may be boiled down into a tug of war, lasting billions of years, between two basic forces. In your own words, describe these forces, and identify which of the two eventually "wins" the battle.
Answer:
Stars are very massive stellar objects, which means that they have a very intense force of gravity. This is the first of the forces entering this "war".
In addition to that, due to the force of gravity that drives the star to contract, the process known as fusion occurs (the union of atoms of one element that results in another element, hydrogen fuses in stars to produce helium). The fusion created in the high temperatures of the center of the star generates an enormous amount of energy (which causes the stars to shine) and a force going outward of the star counteracting gravity, this is the second force in the "war" .
In a stable star these two forces (gravity going inward and the pressure created by the fusion going outward ) are in balance, preventing the star from exploding or collapsing. But eventually the star exhausts its "fuel" (hydrogen atoms) to produce fusion within it (although stars also fuse helium and other heavier elements, but once the hydrogen is finished the star is near its end), which decreases the force outward from the star, making the force that wins this battle to be the force of gravity.
When the force of gravity wins, the star collapses on itself and from here, depending on the star's mass, several things can happen, such as the star becoming a white dwarf, a supernova, even a black hole.
The life cycle of stars may be boiled down into a tug of war, lasting billions of years, between two basic forces -
Pressure due to fusion reactions pushes outwards.Gravity pulls inwards to keep the star in equilibrium.And gravity wins the battle in the end.Stars are very massive stellar objects and remain the longest in the stage when it is burning Hydrogen into Helium.
Stars have a very intense force of gravity that drives the star to contract, the process known as fusion occurs.Due to fusion, high temperatures of the center of the star create an enormous amount of energy and a force of pressure going outward of the star counteracting gravityGravity going inward and the pressure created by the fusion going outward is in balance, preventing the star from exploding or collapsing.Due to exhausting hydrogen atoms, fusion stops eventually and it decreases the force outward from the star, making the force that wins this battle to be the force of gravity.Thus,
The life cycle of stars may be boiled down into a tug of war, lasting billions of years, between two basic forces -
Pressure due to fusion reactions pushes outwards.Gravity pulls inwards to keep the star in equilibrium.And gravity wins the battle in the end.Learn more:
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Rafael swings a baseball bat with a force of 25 N. The baseball bat exerts a force of 5 N on the baseball. What is the mechanical advantage of the baseball bat? The mechanical advantage of the baseball bat is
Answer:
0.2
Explanation:
Mechanical Advantage is defined as the ratio of force output with respect to the force input. Thus,
MA = output / input
MA = 5 / 25
MA = 1/5
MA = 0.2
Since this value is less then one. Even though it's tagged a mechanical advantage, in reality it would be mechanical disadvantage.
Therefore, we can say that the mechanical advantage of the baseball bat is 0.2
Answer:
0.2
Explanation:
How far can you get away from your little brother with a paintball marker if you can travel at 3 m/s and you have 15s before he sees you?
which factors affect the strength of magnetic field around current carrying wire?
Explanation:
The expression for the magnetic field around the current carrying wire is given by :
[tex]B=\dfrac{\mu_o I}{2\pi r}[/tex]
Here,
I is electric current and r is distance from the wire.
The factors affect the strength of magnetic field around current carrying wire are :
Electric currentDistance from wireWhich phrases describe all the outer planets’ motion? Select two options.
no rotation
fast rotation
slow revolution
opposite revolution
north to south rotation
Answer:
Fast rotation
Slow revolution
Explanation:
Solar system has 8 planets. 4 inner rocky planets - Mercury, Venus, Earth and Mars and 4 outer gaseous planets - Jupiter, Saturn, Uranus and Neptune. The outer planets have few common features.
They are gaseous. There period of revolution is larger than the inner planets which means that they have slow revolution about the Sun. One day on the outer planets is smaller than the inner planets which means they have fast rotation.
For example, Jupiter has revolves around sun in 11.86 Earth years and rotates about axis in 9.8 Earth hours. Uranus revolves around sun in 84 Earth years and rotates on its axis 17.9 Earth hours.
Answer:
Fast rotation
Slow revolution
Explanation:
did the test
An ice skater spins at 2.5 rev/s when his arms are extended. He draws his arms in and spins at 10.0 rev/s. By what factor does his moment of inertia change in the process?
Answer:
The moment of inertia decreased by a factor of 4
Explanation:
Given;
initial angular velocity of the ice skater, ω₁ = 2.5 rev/s
final angular velocity of the ice skater, ω₂ = 10.0 rev/s
During this process we assume that angular momentum is conserved;
I₁ω₁ = I₂ω₂
Where;
I₁ is the initial moment of inertia
I₂ is the final moment of inertia
[tex]I_2 = \frac{I_1 \omega_1}{\omega_2} = \frac{I_1*2.5}{10} \\\\I_2 = 0.25I_1 = \frac{1}{4}I_1[/tex]
Therefore, the moment of inertia decreased by a factor of 4
A popcorn-maker transfers 250 J of energy into other energy stores every second. What is its power?
Answer: 250 watts
Explanation:
energy=250J
Time=1 sec
Power=energy ➗ time
Power=250 ➗ 1
Power=250
Power is 250 watts
According to the question,
Energy,
250 JTime,
1 secondThe formula,
→ [tex]Power =\frac{Energy}{Time}[/tex]
By substituting the values, we get
[tex]= \frac{250}{1}[/tex]
[tex]= 250 \ Watts[/tex]
Thus the above approach is right.
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Two scientists decide to investigate the rate at which objects fall on different planets. They choose to use Earth and Mars as case studies. One scientist stays on Earth and the second goes to Mars. Each of them released a 2kg piece of stone at a height of 15 metres from the surface of the planet at exactly the same time. On which planet will the stone hit the ground first? Why do you think so?
Answer:
the stones are released from rest at the same time, the stone that is on Earth to have more acceleration must first reach the ground
Explanation:
For this exercise we will use the law of universal attraction on each planet and Newton's second law to calculate the body's acceleration on each planet
F = ma
F = G m M / r²
Where G is the universal gravitational constant, m the mass of the body, M the mass of the planet and r the distance
Let's start with the Earth
G m M / r² = m a
a = G M / r²
let's look for the distance
r = [tex]R_{e}[/tex] + h
a = G M / (R_{e} + h)² = (G M /R_{e}²) 1 /(1 + h /R_{e})² ²
as h << R_{e} we can expand this function
(1 + h /R_{e})⁻² = 1 -2 h / Re + ...
with h /R_{e} it is very small we can despise it
a = G M /R_{e}
the amount in parentheses is called the acceleration due to gravity
g = G M / R_{e}²
g = 6.67 10⁻¹¹ 5.98 10²⁴ / (6.37 10⁶)²
g = 9.8 m / s ²
Now let's calculate the acceleration on Mars, let's use index 2 for this planet
a = G M2 / R_{2}²
a = 6.67 10⁻¹¹ 6.42 10²³ / (3.37 10⁶)
a = 3.77 m / s²
Let's analyze these results as the stones are released from rest at the same time, the stone that is on Earth to have more acceleration must first reach the ground
we can use the equation
y = v₀ t - ½ to t2
v₀ = 0
t = √ (2y / a)
we see that as the acceleration is greater the time decreases
Work out the kinetic energy of a 2.5 kg remote-controlled car that is moving at 2 m/s.
Answer: 5 joules
Explanation:
mass=m=2.5kg
Velocity=v=2m/s
Kinetic energy=ke
ke=(m x v x v)/2
ke=(2.5 x 2 x 2)/2
Ke=10/2
Ke=5
Kinetic energy=5 joules
The kinetic energy of a 2.5 kg remote-controlled car that is moving at 2 m/s is 5 Joules.
What is kinetic energy?The energy which an item has as a function of motion is determined by the initial energy. It is described as the effort required to propel a material body from rest to the given velocity.
It is given that:
Mass of the remote-controlled car = 2.5 kg
Velocity of the car = 2 m/s
As we know,
Kinetic energy = k
k = (mv²)/2
As we know,
The mass is a tangible body's mass is the amount of matter it possesses. It's also a metric of inertia or the resistance to velocity when a net force is exerted.
m = 2.5 kg
v = 2 m/s
k = (2.5×2²)/2
k = 10/2
k = 5 Joules
Thus, the kinetic energy of a 2.5 kg remote-controlled car that is moving at 2 m/s is 5 Joules.
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4. The batteries on electric vehicles are recharged using electricity from either a wall socket or dedicated charging
unit.
A) O True
B) O False
Answer:
Hey!
Your answer is A) TRUE!
Explanation:
The electricity in this instance is called "grid-electricity" because it has come from a generation plant elsewhere instead of recharging the batteries via Kinetic/Potential energy...
The graph to the right represents the change in velocity of four cars over a period of 10 hours. Which line represents the car with the greatest acceleration?
A. A C. C
B. B D. D
Please help me
Answer:
there is an option for uploading the pic of a diagram while posing any question on brainly. hope you use that feature of the app to upload graph of your question so that it can be well answered
Answer: It’s A!
Explanation: I took the test
An air-track glider attached to a spring oscillates between the 10.0 cm mark and the 61.0 cm mark on the track. The glider completes 11.0 oscillations in 31.0 s
Answer:
T = 2.82 seconds.
The frequency [tex]\mathbf{f = 0.36 \ Hz}[/tex]
Amplitude A = 25.5 cm
The maximum speed of the glider is [tex]\mathbf{v = 56.87 \ rad/s}[/tex]
Explanation:
Given that:
the time taken for 11 oscillations is 31 seconds ;
SO, the time taken for one oscillation is :
[tex]T = \frac{31}{11}[/tex]
T = 2.82 seconds.
The formula for calculating frequency can be expressed as :
[tex]f = \frac{1}{T}[/tex]
[tex]f = \frac{1}{2.82}[/tex]
[tex]\mathbf{f = 0.36 \ Hz}[/tex]
The amplitude is determined by using the formula:
[tex]A = \frac{d}{2}[/tex]
The limits that the spring makes the oscillations are from 10 cm to 61 cm.
The distance of the glider is, d = (61 - 10 )cm = 51 cm
Replacing 51 for d in the above equation
[tex]A = \frac{51}{2}[/tex]
A = 25.5 cm
The maximum speed of the glider is:
[tex]v = A \omega[/tex]
where ;
[tex]\omega = \frac{2 \pi}{T}[/tex]
[tex]\omega = \frac{2 \pi}{2.82}[/tex]
[tex]\omega = 2.23 \ rad/s[/tex]
[tex]v = A \omega[/tex]
[tex]v = 25.5 *2.23[/tex]
[tex]\mathbf{v = 56.87 \ rad/s}[/tex]
