Answer:
Black bodies are good absorber of light waves from the sun, while shining surfaces are good reflector of the light waves.
Explanation:
Generally, a black surface or material tends to absorb light waves while under the sun, while a shiny surface is a good reflector of the waves. This is because the black material is a good absorber, and also a good emitter.
The shiny necklace can only absorb little light waves from the sun, thus it reflects most of the light waves. The reflection is the reason for the small circles of light seen around the yard.
However, when in a cool environment the black shirt would cools faster (good emitter) than the shiny necklace.
A forklift was used to lift a 750 kg. oil drum 18 m straight up into the air to store on a shelf. If it does it in 28 seconds, Calculate the work and power exerted by the forklift.
W= J
P= watts
Explanation:
Given parameters:
Mass of forklift = 750kg
Height of lift = 18m
Time taken = 28s
Unknown:
Work done = ?
Power = ?
Solution;
The work done by the forklift is given as:
Work done = mass x acceleration due to gravity x height
Work done = 750 x 9.8 x 18 = 132300J
Power is the rate at which work is done;
Power = [tex]\frac{work done }{time}[/tex]
Insert the parameters and solve;
Power = [tex]\frac{132300}{28}[/tex] = 4725W
If an object is not moving, the forces acting upon it are...
A.Balanced
B. Weak
C.Unbalanced
D.Hulk SMASH!
What is the impact of age on flexibility? A. Younger people tend to develop flexibility more slowly. B. Younger people tend to be more flexible. C. Older people tend to be more flexible. D. Older people cannot maintain their flexibility.
Answer:
the answer is b
Explanation:
A 75.0kg diver falls from a 3.00m board into the water. She goes 2.40m into the water before stopping. What is the average force the water exerted on the diver?
Answer:
The potential energy of the diver at the top is equal to the net work needed to be done to stop the diver.
PE = W
mg(h+d) = Fd
Explanation:
Something that causes significant personal stress, appears strange to others,
and
is a psychologícal disorder.
O A. is a split from reality
OB. impairs one's ability to function
OC. includes hallucinations
OD. happens across cultures
Answer:
Impairs one's ability to function
Explanation:
Answer:
Impairs one's ability to functionExplanation:
I just took the test
The movie "The Gods Must Be Crazy" begins with a pilot dropping a bottle out of an airplane. A surprised native below, who thinks it is a message from the gods, recovers it. If the plane from which the bottle was dropped was flying at a height of 500 m, and the bottle lands 400 m horizontally from the initial dropping point, how fast was the plane flying when the bottle was released? Draw a 2-dimensional motion map for the velocities and another for the acceleration.
Answer:
1) The Speed of the plane is approximately 39.596 m/s
2) Please find attached the required velocity and acceleration graphs
Explanation:
1) The height at which the plane was flying, h = 500 m
The location the bottle lands from the initial dropping point = 400 m
The time it takes the bottle to land is given by the equation for free fall as follows;
h = 1/2·g·t²
Where;
g = The acceleration due to gravity = 9.8 m/s²
t = √(h/(1/2·g) = √(500/(1/2×9.8) ≈ 10.102
The Speed of the plane = The horizontal velocity of the bottle = 400/10.102 ≈ 39.596
The Speed of the plane ≈ 39.596 m/s
2) Please find attached the velocity graph for the vertical and horizontal velocities of the bottle and the acceleration graph for the vertical motion of the bottle, created with Microsoft Excel
Why d/dt(a+bt^2)=2bt
Because a is not a function of t .
So d/dt of a is zero.
A concrete block of mass 35kg is pulled along a horizontal floor with the aid of a rope inclined at an angle of 30⁰ to the horizontal. If the coefficient of friction is 0.75, Calculate the force required to move the block( g = 10 ms⁻²)
A. 401.5 N
B. 226.5 N
C. 211.5 N
D. 245. 7N
Answer:
C. 211.5 N
Explanation:
We included a free body diagram representation of the concrete block. The equation of equilibrium in the x-direction:
[tex]\Sigma F_{x} = P\cdot \cos \alpha -\mu_{k}\cdot N = m\cdot a[/tex] (1)
[tex]\Sigma F_{y} = N + P\cdot \sin \alpha -m\cdot g = 0[/tex] (2)
Where:
[tex]P[/tex] - External force exerted on the block, measured in newtons.
[tex]N[/tex] - Normal force from the ground to the block, measured in newtons.
[tex]\alpha[/tex] - Direction of the external force, measured in sexagesimal degrees.
[tex]\mu_{k}[/tex] - Kinetic coefficient of friction, dimensionless.
[tex]m[/tex] - Mass of the concrete block, measured in kilograms.
[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.
[tex]a[/tex] - Net acceleration of the concrete block, measured in meters per square second.
The minimum force to move block occurs when net force is zero, from (2) we get that the normal force is:
[tex]N = m\cdot g -P\cdot \sin \alpha[/tex]
And by applying this formula in (1), we get that the external force is:
[tex]P\cdot \cos \alpha - \mu_{k}\cdot (m\cdot g -P\cdot \sin \alpha) = m\cdot a[/tex]
[tex]P\cdot \cos \alpha -\mu_{k}\cdot m\cdot g +\mu_{k}\cdot P\cdot \sin \alpha = 0[/tex]
[tex]P\cdot (\cos \alpha +\mu_{k}\cdot \sin \alpha)=\mu_{k}\cdot m\cdot g[/tex]
[tex]P = \frac{\mu_{k}\cdot m\cdot g}{\cos \alpha +\mu_{k}\cdot \sin \alpha}[/tex]
If we know that [tex]\mu_{k} = 0.75[/tex], [tex]m = 35\,kg[/tex], [tex]g = 10\,\frac{m}{s^{2}}[/tex] and [tex]\alpha = 30^{\circ}[/tex]. then the external force is:
[tex]P = \frac{(0.75)\cdot (35\,kg)\cdot \left(10\,\frac{m}{s} \right)}{\cos 30^{\circ}+0.75\cdot \sin 30^{\circ}}[/tex]
[tex]P \approx 211.518\,N[/tex]
The correct answer is C.
For a given force as time ___
the impulse related to that force increases. *
A. increases
B. decreases
Answer:
Increases
Explanation:
For a given force, as the time increases, the impulse related to that force increases also.
Impulse and time are directly related to one another. Impulse is mathematically given as:
I = F t
I is the impulse
F is the force
t is the time taken
So, as both force and time increases, the value of the impulse must increase.
A hammer strikes a nail with a 8 N force for 0.018 seconds. Calculate the impulse of the hammer.
Answer:
0.144
Explanation:
Impulse is defined as force multiplied by time
please mark me brainliest
Give an example of a situation in which you have experienced sound being reflected, absorbed, and transmitted.
Answer: Absorption is the transformation of radiant power to another type of energy, usually heat, by interaction with matter. The transmittance t of a medium is defined by the ratio of transmitted radiant power to incident radiant power.
Explanation:
Absorption, in wave motion, the transfer of the energy of a wave to matter as the wave passes through it. ... If there is only a small fractional absorption of energy, the medium is said to be transparent to that particular radiation, but, if all the energy is lost, the medium is said to be opaque.
How can you drop two eggs the fewest amount of times, without them breaking?
Answer:
Both eggs are identical. The aim is to find out the highest floor from which an egg will not break when dropped out of a window from that floor. If an egg is dropped and does not break, it is undamaged and can be dropped again. However, once an egg is broken, that's it for that egg.
what's newtons second law
Newton's Second Law of Motion states "The rate of change of momentum of a body is directly proportional to the applied unbalanced force in the direction of force".
Conclusion When there is a constant unbalanced force applied in the same direction as the motion, speed will ___________________ and acceleration will _____________________________. When there is an increasing unbalanced force applied in the same direction as the motion, speed will ___________________ and acceleration will ________________________. When there is a constant unbalanced force applied in the opposite direction as the motion, speed will ___________________ and acceleration will ________________________. When there is an increasing unbalanced force applied in the opposite direction as the motion, speed will ___________________ and acceleration will ________________________.
Explanation:
When there is a constant unbalanced force applied in the same direction as the motion, speed will increase and acceleration will remain constant. When there is an increasing unbalanced force applied in the same direction as the motion, speed will increase and acceleration will increase.
According to newton's 2nd law
F = ma
F ∝ a
meaning when F increases , a increases and vice versa
The si unit of mass is the Newton. True or false.
1) A person slides a box down a ramp. The box starts from rest 2m above the lowest
point. The ramp is frictionless, Once the box reaches the bottom there is friction
For every 1m the box travels on the flat part Eint increases by 100). Where does the
box stop? The box has mass of 5 kg.
Answer:
.98m
Explanation:
a car accelerates from rest to 90 kilometre per hour in 10 seconds what is its acceleration in metre per second squared
Answer:2.5 m/s2
Explanation:
Acceleration =v2-v1 ÷ t2-t1 convert 90 km/h to m/s = 90×5/18 = 25 m/s , 25÷10 = 2.5
Which statement compares the attractive forces that hold particles together?
Explain how skeletal muscles work in pairs.
plzzzz answer asap !!
Answer:
it holds the bone and helps to move
I don't know if this is right
When two polarizers are overlapped, what angle relative to one another will allow for all of the incoming light to be blocked? *
Answer:
90°
Explanation:
The intensity of the transmitted light is proportional to the square of the cosine of the angle between polarizer axes. That cosine is zero when the angle is 90°.
which two statement descibe processes most likely to be involved in the formation of sedimentary rock?
Answer:
Erosion
Explanation:
Sedimentary rocks are created from the build up of sediments, such sediments can be found in stuff like soil, other rocks and many more. Erosion is involved in these type of rocks because the byproduct of erosion are sediments.
Answer:
Rivers... and Windstorms....
Explanation:
I just did it a p e x
Heat transfers through Earth's systems in different ways. In which atmospheric action can we see evidence of conduction? Cold air pushes warm air upward, creating a current. Cold air pushes warm air upward, creating a current. The surface of the Earth heats the air that contacts it. The surface of the Earth heats the air that contacts it. Radiation from the Sun heats the surface of the Earth. Radiation from the Sun heats the surface of the Earth. Air increases in density and sinks back towards the Earth.
Answer:
B. The surface of the Earth heats the air that contacts it.
Explanation:
Conduction is a mode of heat transfer in which energy is transferred from a hot molecule to the neighboring molecules due to contact. Thus, heat energy is transferred from one molecule to another in the process.
Therefore, the air that comes in contact with the surface of the earth heats up by conduction. Since the surface of the earth is heated up due to the radiation from the Sun.
Answer: B.
Explanation: I took the test. Also, after my diagnostic I just wanted to see if my answers were correct lol.
The pattern shown in the photo is the result of a time-lapsr video of a clear night sky
Which mostly likely causes the apparent motion of the stars seen in this photo?
A. Earth's revolution around the Sun
B. The revolution of the Stars around the Sun
C. Earth's rotation on its axis
D. The revolution of the stars
around Earth
Answer:
C.
Explanation:
Answer:
C
Explanation:
The earths rotation on its axis
4) What amount of energy is radiated by the sun per second
Answer:
"The sun releases energy at a mass–energy conversion rate of 4.26 million metric tons per second, which produces the equivalent of 384.6 septillion watts (3.846×1026 W)."
Explanation:
This might help you, also this is searched.
What happens when plate subducts and reaches the mantle
Answer:
burns
Explanation:
Two carts connected by a 0.25 m spring hit a wall, compressing the spring to 0.1 m. The spring constant k is 100 N m . What is the elastic potential energy stored from the spring's compression?
Given that,
Initial position of the spring, x₁ = 0.25 m
Final position of the spring, x₂ = 0.1 m
The spring constant of the spring, k = 100 N/m
To find,
The elastic potential energy stored from the spring's compression.
Solution,
The work done in moving a spring from on position to another is stored in the form of elastic potential energy. It can be given as follows :
[tex]E=\dfrac{1}{2}k(x_2^2-x_1^2)\\\\=\dfrac{1}{2}\times 100\times (0.1^2-0.25^2)\\\\=2.62\ J[/tex]
So, the required energy is 2.62 J.
Answer:
1.125 J
Explanation:
The correct answer is 1.125 J
A rectangular tank is filled with water to a depth of 4m. Calculate the pressure at the bottom of the tank. PLEASEEE HELP!! IM BEGGING!!!! PLEASEEEEE
For this we have the hidrostatic equation:
[tex]\boxed{P = \rho gh}[/tex]
Being:
P = Pressure
ρ = Density of liquid (water) = 1000 kg/m
g = Gravity = 9,81 m/s²
h = Height = 4 m
Replacing acording formula:
[tex]\boxed{P = 1000 \ kg/m ^{3} * 9,81 \ m/s^{2} * 4 \ m}[/tex]
Resolving:
[tex]\boxed{P = 39240 \ Pa}[/tex]
Result:
The pression at the bottom is 39240 Pa.
What happens to thermal energy when Kinetic energy is Increased/Decreased?
Answer:If kinetic energy increases, so does the thermal energy, and vice versa.
Please brainliest!
How does hydropower generate electricity?
Answer:
the water spins the wheel wiche gives energy.
Explanation:
Which statement correctly compares radio waves and microwaves?
A. Radio waves have shorter wavelengths and lower frequencies than microwaves.
B. Radio waves have longer wavelengths and higher frequencies than microwaves.
C. Radio waves have longer wavelengths and lower frequencies than microwaves.
D. Radio waves have shorter wavelengths and higher frequencies than microwaves.
Answer:
C. Radio waves have longer wavelengths and lower frequencies than microwaves.
Explanation:
Radio waves and microwaves are both electromagnetic waves. They do not require a medium for their propagation.
These waves are produced as result of the vibration between electric and magnetic fields perpendicular to one another.
On the electromagnetic spectrum, the waves are listed from left to rightAlong the spectrum, wavelength increases as frequency decreases. Energy also decreases to the right on the spectrum. Since microwaves comes before radio waves, they have shorter wavelength and higher frequency than micro waves.