Answer:
17
Explanation:
2 x 10 = 20
20-3 = 17
A construction laborer holds a 20 kg sheet of wallboard 3 m above the floor for 4 seconds. During these 4 seconds how much power was expended on the wallboard
Answer:
zero
Explanation:
no distance has moved while holding the sheet...so no distance means no workdone..no workdone means no power...
A force can change an object's direction and cause friction
True or False
Answer:
This is very true
Explanation:
The force from impact can easily change it to expanse in a different direction.
I hope this helped you very much :)
Help Help!!
Alcohol ___ the central nervous system and the peripheral nervous system.
A. sedates
B. stimulates
C. bypasses
Answer:
I think it is the answer A
Explanation:
Alcohol won't stimulate the central nervous system and the peripheral nervous system because the fact that the brain and the nervous system are affected can lead to many consequences: disorders of vision, hearing, motor coordination ...
Alcohol will therefore have a damaging effect, it will therefore sedate the nervous system.
Answer:A
Explanation:sedates
1. Calculate the momentum of a 1.0 kg object moving with a velocity of +20 m/s.
2. What is the velocity of an object that has a momentum of -30 kg m/s and a mass of 3.0 kg?
3. Two objects have equal momentum but one has four times the mass of the other. What is the relationship between
their velocities?
4. Which answer below shows the correct units for momentum?
A. kg m/s
B. kg m/s?
C. kg m/s
D. kg s/m
5. Two bowling balls each have a mass of 4.0 kg
The red Bar is moving east 2.0 m/s. The blue ball is moving west at 1.0 m/s. Calculate the total momentum of the system.
Answer:
1)1*20=20
2)-30/3=- -10
3)velocity of the object 1=v1=4*V2
4) kg m/ s
5) momentum of the system= 12 kg m/ s
A projectile is fired with a velocity of 8 m/s at an angle of 65º. What is the
vertical component of the velocity?
A. 6.5 m/s
B. 3.4 m/s
C. 10.2 m/s
D. 7.2 m/s
Answer:
i think its D
Explanation:
Calculate the heat energy needed to change the temperature of 2 kg of copper from 10°C to 110°C.
If you could show your process and equations used, that would be very helpful! Thanks!
Answer:
77000 J
Explanation:
Formula for the heat energy is;
Q = m•c•Δt
We are given;
mass; m = 2 kg
Change in temperature; Δt = 110 - 10 = 100 °C
From online values, specific heat capacity of copper is; c = 385 J/kg.°C
Thus;
Q = 2 × 100 × 385
Q = 77000 J
Answer:
heat = 20 Kcal
Explanation:
horizontal range = 200m, maximum height= 25m find the angle of projection.
Answer:
θ = 26.6°
Explanation:
Formula for maximum height is;
h = u²sin²θ/2g
We are told maximum height is 25 m, thus;
u²sin²θ/2g = 25 - - - - (eq 1)
Formula for horizontal range is;
R = u²sin2θ/g
In Mathematics, sin2θ = 2sinθcosθ
So; R = 2u²sinθcosθ/g
R = 2u²sinθcosθ/g
We are given Horizontal range = 200 m.
Thus;
2u²sinθcosθ/g = 200 - - - - (eq 2)
Divide eq 1 by eq 2 to get;
200/25 = 4cosθ/sinθ
8 = 4cosθ/sinθ
4/8 = sinθ/cosθ
0.5 = tan θ
θ = tan^(-1) 0.5
θ = 26.6°
Two displacement vectors have magnitudes of 5.0 m and 7.0 m, respectively. If these two vectors are added together, the magnitude of the sum
Answer:
8.6m
Explanation:
Step one:
given data
we are given two displacement vectors of magnitudes 5 and 7m
Let us assume they are in the same direction and they are acting perpendicular to each other.
Step two:
The magnitude of the vector sum is the resultant vector
which is found by
R^2=5^2+7^2
R^2= 25+49
R^2=74
R=√74
R=8.6m
Imagine you were lifting very heavy jugs to the top of a house. You can either use the stairs on the left or push them up the inclined plane on the right. Which option is easier
Answer:
Use the stairs
Explanation:
This is easier because if you go on the stairs you can rest if you get tired but if you go on the inclined plane then the weight of the jugs will make you slower than you already are and you may end up going back down instead of up where you wanna go.
A dynamite blast blows a heavy rock straight up from the ground with a launch velocity of 160ft/sec. a) Write the height function.
Answer:
y = 160t - 16t²
Explanation:
Using y = ut -1/2gt² where y = height of heavy rock above the ground, u = initial launch velocity of rock = 160 ft/s, g = acceleration due to gravity = 32 ft/s² and t = time.
So, substituting the values of the variables into y, we have
y = (160 ft/s)t -1/2 × 32 ft/s² × t²
y = (160 ft/s)t - (16 ft/s²)t²
y = 160t - 16t²
So, the height function is y = 160t - 16t²
helpp please
ASAP...
Answer:
I believe it to be option A
Explanation:
PLEASE HELP ASAP
ILL GIVE BRAINLIEST
2. What are three crucial pieces of evidence that supports the claim for the Big Bang theory. Include a piece of evidence that relates each of the following:
a. Light spectra
b. Motion of distant galaxies
c. Composition of matter in the universe
3. Explain how or why each piece of evidence supports the claim made in Big Bang theory.
Answer:
The evidence that the universe is expanding comes with something called the red-shift of light. Light travels to Earth from other galaxies. As the light from that galaxy gets closer to Earth, the distance between Earth and the galaxy increases, which causes the wavelength of that light to get longer. Distant galaxies are getting further away hinting at a point of origin. The composition of all observed matter in this universe points at a common origin point for all matter in the universe.
The three crucial evidences that supported the Big Bang theory are the CMB or cosmic microwave background, the expanding universe, the abundance of elements in the universe.
What is Big Bang theory ?Big Bang theory is one of the important theory scientists used in earliest to describe the origin of universe and the phenomenon of evolution.
Here,
2. The Big Bang theory described the origin of universe as an expansion from an atmosphere of high density and extreme temperature which lead to a huge explosion of matter known as the 'Big Bang' and thus creation of the universe.
The three crucial evidences that supported the Big Bang theory are:
The CMB or cosmic microwave background, the expanding universe, the abundance of elements in the universe.
3.(a) Light spectra was an important factor that supported the Big Bang theory mainly by the phenomenon called Doppler shift. Doppler shift occurs when stars move away, they get shifted to longer wavelength. This phenomenon is called red-shift or Doppler's Red shift. This was applicable in the case of Big Bang theory such that the theory claimed that, as a result of explosion which is the Big Bang, the material particles move away. This was similar to the red shift.
(b) The motion of distant galaxies was an evidence of the expansion of universe and soo the Big Bang theory. It was explained in such a way that, as the galaxies move away from us, it shows the more expansion of universe and the time duration since the origin of universe.
(c) The composition of matter in the universe was an important evidence that supported the Big Bang theory. The composition of universe that there is high abundance of hydrogen and helium in the atmosphere was claimed by the Big Bang theory.
Hence,
The three crucial evidences that supported the Big Bang theory are the CMB or cosmic microwave background, the expanding universe, the abundance of elements in the universe.
To learn more about Big Bang theory, click:
https://brainly.com/question/1160650
#SPJ2
What are your thoughts about Russia getting banned from the 2020 Olympics and 2022 World cup?
A 15-kg wagon is pulled to the right across a surface by a tension
of 100 newtons at an angle of 30 degrees above the horizontal.
A frictional force of 20 newtons to the left acts simultaneously.
What is the acceleration of the wagon?
Answer:
4.44 m/s^2
Explanation:
A 15-kg wagon is pulled to the right across a surface by a tension of 100 newtons at an angle of 30 degrees above the horizontal. A frictional force of 20 newtons to the left acts simultaneously.The acceleration of the wagon 4.44 m/s².
What is acceleration?The rate at which an item changes its velocity is known as acceleration, a vector quantity. If an object's velocity is changing, it is acceleration.
Given in the question a 15 kg wagon is pulled to the right across a surface by a tension of 100 newtons at an angle of 30 degrees above the horizontal. A frictional force of 20 newtons to the left acts simultaneously, then the acceleration is 4.44 m/s².
The acceleration of the wagon 4.44 m/s².
To learn more about acceleration refer to the link:
brainly.com/question/12550364
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A boat moves through the water of a river at 8 m/s relative to the water, regardless of the boat's direction. If the water in theriver is flowing at 1.9 m/s, how long does it take the boat to makea round trip consisting of a 260 m displacement downstream followedby a 260 m
Answer:
68.88 m/s
Explanation:
downstream speed = 8+1.9=9.9 m/s
upstream speed = 8-1.9= 6.1 m/s
Therefore, total time taken would be 260/9.9+260/6.1 = 26.26+42.62 =
68.88 m/s
How many types of rocks make up the Earth's crust?
Answer:
3, it's the igneous rock, sedimentary rock, and metamorphic rock i believe
Explanation:
Answer:
igneous, sedimentary, and metamorphic.
Explanation:
The intensity at a distance of 6 m from a source that is radiating equally in all directions is 6.0\times 10^{-10} W/m^2. What is the power emitted by the source
Answer:
P = 271 nW
Explanation:
If the source is radiating equally in all directions, it can be treated as a point source, so all points located at the same distance of the source, have the same intensity I, which is related to the power by the following expression:[tex]I = \frac{P}{A} =\frac{P}{4*\pi *r^{2} } (1)[/tex]
Solving for P, we get:[tex]P = I*4*\pi *r^{2} = 6.0e-10 W/m2 * 4 * \pi *(6m)^{2} =271 nW (2)[/tex]
A(n) 636 kg elevator starts from rest. It moves upward for 4.5 s with a constant acceleration until it reaches its cruising speed of 2.05 m/s. The acceleration of gravity is 9.8 m/s 2 . Find the average power delivered by the elevator motor during this period. Answer in units of kW.
Answer:
The average power delivered by the elevator motor during this period is 6.686 kW.
Explanation:
Given;
mass of the elevator, m = 636 kg
initial speed of the elevator, u = 0
time of motion, t = 4.5 s
final speed of the elevator, v = 2.05 m/s
The upward force of the elevator is calculated as;
F = m(a + g)
where;
m is mass of the elevator
a is the constant acceleration of the elevator
g is acceleration due to gravity = 9.8 m/s²
[tex]a = \frac{v-u}{t} \\\\a = \frac{2.05 -0}{4.5} \\\\a = 0.456 \ m/s^2[/tex]
F = (636)(0.456 + 9.8)
F = (636)(10.256)
F = 6522.816 N
The average power delivered by the elevator is calculated as;
[tex]P_{avg} = \frac{1}{2} (Fv)\\\\P_{avg} = \frac{1}{2} (6522.816 \ \times \ 2.05)\\\\P_{avg} = 6685.89 \ W\\\\P_{avg} = 6.68589 \ kW\\\\P_{avg} = 6.686 \ k W[/tex]
Therefore, the average power delivered by the elevator motor during this period is 6.686 kW.
Which describes velocity?
Answer:
Velocity is the rate at which the position changes. The average velocity is the displacement or position change per time ratio.
Explanation:
Answer:
The velocity of an object is the rate of change of its position with respect to a frame of reference, and is a function of time. Velocity is equivalent to a specification of an object's speed and direction of motion (e.g. 60 km/h to the north).
Other units: mph, ft/s
In SI base units: m/s
Explanation:
i dont know if this helps.
is this right? plzz anwser soon
Answer:
yes
Explanation:
Answer:
y e p
Explanation:
A metallic ring of mass 1 kg has moment of inertia 1 kg m² when rotating about one of its diameters. It is molten and
remoulded into a thin uniform disc of the same radius. How much will its moment of inertia be, when rotated about its own
axis.
Answer:
The moment of inertia of disc about own axis is 1 kg-m².
Explanation:
Given that,
Mass of ring m= 1 kg
Moment of inertia of ring at diameter [tex](I_{r})_{d}=1\ kg\ m^{2}[/tex]
The radius of metallic ring and uniform disc both are equal.
So, [tex]R_{r}=R_{d}[/tex]
We need to calculate the value of radius of ring and disc
Using theorem of perpendicular axes
[tex](I_{r})_{c}=2\times (I_{r})_{d}[/tex]
Put the value into the formula
[tex](I_{r})_{c}=2\times1[/tex]
[tex](I_{r})_{c}=2\ kg\ m^2[/tex]
Put the value of moment of inertia
[tex]MR_{r}^2=2[/tex]
[tex]R_{r}^2=\dfrac{2}{M}[/tex]
Put the value of M
[tex]R_{r}^2=\dfrac{2}{1}[/tex]
So, [tex]R_{r}^2=R_{d}^2=2\ m[/tex]
We need to calculate the moment of inertia of disc about own axis
Using formula of moment of inertia
[tex]I_{d}=\dfrac{1}{2}MR_{d}^2[/tex]
Put the value into the formula
[tex]I_{d}=\dfrac{1}{2}\times1\times2[/tex]
[tex]I_{d}=1\ kg\ m^2[/tex]
Hence, The moment of inertia of disc about own axis is 1 kg-m².
The wavelength of a particular color of violet light is 417 nm. The energy of this wavelength of light is
Answer:
E = 4.7 x [tex]10^{-19}[/tex] Joules
Explanation:
Solution:
The wavelength of a particular color of violet light = 417 nm
What is the energy = ?
In order to calculate energy, we will use the following formula:
E = hf
where, f = frequency = 1/wavelength = c/λ
where c = speed of light = 299 792 458 m / s or 3 x [tex]10^{8}[/tex] m/s
where h = Plank's constant = 6.62x [tex]10^{-34}[/tex] [tex]m^{2}[/tex] kg / s
So,
λ = 417 nm
1 nm = [tex]10^{-9}[/tex] m
so,
λ = 417 x [tex]10^{-9}[/tex] m
Now, just plug in the values to calculate the energy of this wavelength of light.
E = hc/λ
E = ( 6.62x [tex]10^{-34}[/tex] ) (299 792 458) / (417 x [tex]10^{-9}[/tex] )
E = 0.047 x[tex]10^{-17}[/tex]
E = 4.7 x [tex]10^{-19}[/tex] Joules
diffrence between:- movable pulley and fixed pully
Answer:
fixed pulley: A pulley system in which the pulley is attached to a fixed point and the rope is attached to the object. ... movable pulley: A pulley system in which the pulley is attached to the object; one end of the rope is attached to a fixed point and the other end of the rope is free.
Explanation:
which is not an insulator?
A wood
B plastic foam
C aluminum foil
D fiberglass
Answer:the answer is C aluminum foil
Explanation:
5) Choose the best revision of the following statement: "All the isotopes of a particular element decay radioactively by
emitting electrons."
A. All the isotopes of a particular element are stable and do not decay.
B. Some isotopes are stable and others are unstable. Unstable isotopes decay by emitting various subatomic
particles and radiation
C. Some isotopes are stable and others are unstable. Unstable isotopes decay by emitting protons or
electrons.
D. The statement is correct as it is currently written.
Answer:
B. some isotopes are stable and others are unstable. unstable isotopes decay by emitting various subatomic particles and radiation.
Explanation:
test gave me the answer so yeah :/ XD
If a small motor does 520 J of work to move a toy car 260 m, what force does the engine exert on the car?
Answer:
2 NExplanation:
The force engine exert on the car can be found by using the formula
[tex]f = \frac{w}{d} \\ [/tex]
w is the workdone
d is the distance
From the question we have
[tex]f = \frac{520}{260} = 2 \\ [/tex]
We have the final answer as
2 NHope this helps you
3. Missy Diwater, the former platform diver for the Ringling Brother's Circus, had a kinetic energy of 12,000 ) just prior to hitting the bucket of water. If Missy's mass is 40 kg, then what is her speed?
Answer:
v = 24.49[m/s]
Explanation:
We must remember that kinetic energy can be calculated by means of a mathematical expression, which relates kinetic energy to mass and velocity
[tex]E_{kin}=\frac{1}{2}*m*v^{2} \\[/tex]
where:
Ekin = kinetic energy = 12000 [J]
m = mass = 40 [kg]
v = velocity [m/s]
[tex]12000=\frac{1}{2} *40*v^{2}\\24000=40*v^{2}\\600=v^{2}\\v=\sqrt{600}\\v=24.49[m/s][/tex]
A 1000 kg car crashed into a barrier. The car changed speed from 30 m/s to 20 m/s in 0.2 seconds. What force did the barrier apply to stop the car?
Answer:
Force = -50000 Newton
Explanation:
Given the following data;
Initial velocity, u = 30 m/s
Final velocity, v = 20 m/s
Time = 0.2secs
Mass = 1000 kg
First of all, we have to solve for its acceleration.
Acceleration = (v - u)/t
Substituting into the equation, we have
Acceleration = 20 - 30)/0.2
Acceleration = -10/0.2
Acceleration = -50m/s²
To find the force;
Force = mass * acceleration
Force = 1000 * (-50)
Force = -50000 Newton. The value of the force is negative because it stopped the motion of the car.
Therefore, the barrier applied a force of -5,0000 Newtons to stop the car.
Answer: -50000
Explanation:
A 75 kg person climbs the 248 steps to the top of the Cape Hatteras lighthouse, a total climb of 59 m. How many Calories does he or she burn
Answer:
W = 41.45 Kcal
Explanation:
Given that,
The mass of a person, m = 75 kg
He climbs 248 steps to the top of the Cape Hatteras lighthouse, a total climb of 59 m.
We need to find how many calories does he or she burn.
Work done = Fd
d is displacement
⇒ W = 75 ×9.8 ×59
= 43365 J
Let the efficiency is 0.25.
[tex]W=\dfrac{43365}{0.25}\\\\=173460\ J\\\\\text{or}\\\\=41.45\ kcal[/tex]
So, 41.45 Kcal is burned by the person.
A ball falls through the air at terminal velocity. Which of the following are forces that should be included in a free body
diagram? (select all that apply)
air resistance
force of motion
gravity
force of fall
Answer:
air resistance and gravity.
Explanation:
When the ball is falling down at terminal velocity, the velocity is constant.
This means that the net force acting on the ball will be zero (there is no acceleration)
In this situation, there are only two forces that can act on the ball.
The gravitational force, that pulls the ball down.
The air resistance which opposes to the movement of the ball and increases in magnitude as the velocity of the ball increases.
Then there is a point where the velocity of the ball is such that the air resistance is equal in magnitude to the acceleration, and then the net force becomes zero.
Then the two forces that need to be included in this diagram are the air resistance and gravity.