Answer:
c) star explosions.....
A student is constructing an investigation on static electricity. The student has three balloons and rubs two of them on a piece of wool. The student then touches each balloon to the wall to observe if static electricity would cause the balloon to stick. What is the independent variable in this investigation.
Answer:
Explanation:
As given, the student has three balloons and rubs two of them on a piece of wool. The rubbing of balloon on wool is the independent variable as it was done on two and not on the third as control.
why is it not possible to make use of solar cells to meet all of our energy needs?why
Answer:
In the solar cells, the energy is obtained only during the day, when the Sun shines. .So, it increases the cost of using solar panels as the source of energy. So, the solar cell is not used to meet all our energy needs
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Explanation:
Answer:
In the solar cells, the energy is obtained only during the day, when the Sun shines. ... So, it increases the cost of using solar panels as the source of energy. So, the solar cell is not used to meet all our energy needs
Explanation:
n the solar cells, the solar panel convert solar energy into electricity, which is stored in storage battery. The storage battery give the direct current but all the appliances are working by the alternating current, so first of all direct current is converted into alternating current by any suitable appliances before it can be used to run various devices. So it increases the cost of using solar panels as the source of energy.
A rock is thrown down from the top of a cliff with a velocity of 3.61 m/s (down). The cliff is 28.4 m above the ground. Determine the velocity of the rock just before it hits the ground.
The velocity of the rock just before it hits the ground is approximately 23.87m/s.
What is the velocity of the rock just before it hits the ground?From the third equation of motion;
v² = u² + 2gs
Where u is initial velocity, v is final velocity, g is acceleration due to gravity ( g = 9.8m/s² ) and s is distance covered.
Given the data in the question;
Initial velocity u = 3.61m/sHeight of cliff s = 28.4mFinal velocity v = ?To determine the final velocity, plug the given values into the equation of motion above.
v² = u² + 2gs
v² = ( 3.61m/s )² + ( 2 × 9.8m/s² × 28.4m )
v² = 13.0321m²/s² + 556.64m²/s²
v² = 569.6721m²/s²
v = √( 569.6721m²/s²)
v = 23.87m/s
Therefore, the final velocity of the object is 23.87m/s.
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Sports such as football, baseball, soccer, horseback riding, tennis, volleyball, skateboarding, and surfing (to name a few) are full of examples of Newton’s Three Laws of Motion. To answer this question: 1. Choose any sport. Write down the name of the sport. 2. In your own words, state each of Newton’s 3 Laws of Motion and give a clear, specific example of how each law applies to the sport you have chosen.
Answer:
tenis
Tenis applies to each of Newton's 3 Laws of Motion because with the first law if a tenis ball is at rest it will stay at rest unless acted on by an unbalanced force which would be playing tenis in which it would stay in motion. The second law applies since the acceleration at which it is hit times the mass equals the force it has. The third law applies since when hitting a tenis ball back and forth with racquets the reaction may be equal or opposite
What is total internal reflection?
Answer:
When a ray of light, passes from a denser to a rarer medium with the angle of incidence greater than the critical angle, the ray is reflected back into the same medium. This phenomenon is call total internal reflection.
How much kinetic energy is required to break through?
Explanation:
The natural environment or natural world encompasses all living and non-living things occurring naturally, meaning in this case not artificial. The term is most often applied to the Earth or some parts of Earth
Complex matching suggests that individuals who have formed a relationship may differ predominantly in the area of __________.
Answer:
physical attractiveness
Explanation:
how does energy apply to newton’s laws?
Answer:
the acceleration of an object is directly pro to the net force acting on it and indirectingly proportional to its mass
Which statement best explains why there could be a force of attraction
between two electrically charged objects?'
because they have like charges
because they have unlike charges
because they have the same number of protons
because they have the same number of electrons
A Star fleet science officer drops a large rock from a height of 1.55 m onto the surface of an alien planet. The rock strikes the ground in 0.230 s. Determine the acceleration of gravity.
Answer:
58.6 m/s²
Explanation:
Applying,
s = ut+gt²/2............ equation 1
Where s = height of the rock, u = initial velocity, t = time, g = accelration due to gravity of the planet.
From the question,
Given: s = 1.55 m, t = 0.23 s, u = 0 m/s (dropped from an height)
Substitute these values into equation 1
1.55 = (0×0.23)+g(0.23²)/2
1.55 = 0.0529g/2
0.0529g = 3.1
g = 3.1/0.0529
g = 58.6 m/s²
The figure below shows the apparatus used to measure the specific heat capacity of a metal. The electric heater is switched on and supplies 17 000 of thermal energy (heat) to the block of metal. The temperature of the metal rises from 16 °C to 38 °C. The mass of the block of metal is 850 g. No energy is lost from the metal. Calculate the specific heat capacity of the metal.
Answer:
0.909 J/gºC.
Explanation:
From the question given above, the following data were obtained:
Heat (Q) = 17000 J
Initial temperature (T₁) = 16 °C
Final temperature (T₂) = 38 °C
Mass (M) = 850 g
Specific heat capacity (C) =?
Next, we shall determine the change in the temperature of the metal. This can be obtained as follow:
Initial temperature (T₁) = 16 °C
Final temperature (T₂) = 38 °C
Change in temperature (ΔT)
ΔT = T₂ – T₁
ΔT = 38 – 16
ΔT = 22 °C
Finally, we shall determine the specific heat capacity of the metal. This can be obtained as follow:
Heat (Q) = 17000 J
Change in temperature (ΔT) = 22 °C
Mass (M) = 850 g
Specific heat capacity (C) =?
Q = MCΔT
17000 = 850 × C × 22
17000 = 18700 × C
Divide both side by 18700
C = 17000 / 18700
C = 0.909 J/gºC
Therefore, the specific heat capacity of the metal is 0.909 J/gºC.
A 15kg dog jumps out of a 40 kg canoe. If the dog's velocity is 1.2 m/s, what is the velocity of the canoe
Answer:
the velocity is 0.45 m/s and it is moving in the opposite direction
or
-0.45 m/s
Explanation:
The law of conservation of momentum says that initial momentum = final momentum
( mass x velocity of the dog ) = - (mass x velocity of the canoe)
(15 x 1.2) =- (40 x velocity of the canoe)
Velocity of the canoe = -(15 x 1.2) / 40 = -0.45 m/s
16. A student uses 110 N of force to push a box
across a flat room for 7.2 m. Calculate the
amount of work that the student does. Round
your answer to two decimals and show the
correct units of measure.
Answer:
792J
Explanation:
Use the formula Force × Distance
With 110 newtons being the force and 7.2 meters being the distance
Which gives 792 and work us measured in joules therefore its joules
Work done is the dot product of force and displacement. The work done on the box to push across the surface for 7.2 m by applying a force of 110 N is 792 J.
What is force?Force is an external agent acting on a body tp change it from the state of motion or rest. Force is a vector quantity thus, it is characterized by a magnitude and direction.
When force acting on a body results in displacement of the body, it is said to be work done on the body. The work done on the body is the product of force and displacement.
W = F d.
Given the force acting on the box = 110 N
displacement d = 7.2 m
Work done w = 110 N × 7.2 m
= 792 J.
Therefore, the work done on the box is 792 J.
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Sound travels through air at 343 m/s at 20 °C. A bat emits an ultrasonic squeak and hears the echo 0.05 second later . How far away was the object that reflected it?
Answer:
8.575 m
Explanation:
speed = distance/time
distance -- 2d
343 = 2d/0.05
2d = 17.15
d = 17.15/2
d = 8.575
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5. Which energy transformation would friction
cause on a moving train?
A. kinetic energy into thermal energy
B. potential energy into sound energy
C. kinetic energy into potential energy
D. thermal energy into potential energy
Answer:
Fossil fuels store energy from the sun as
Explanation:
Which calculates the intensity of an electric field at a point where a 0.50 C charge experiences a force of 20. N?
Answer: [tex]40\ N/C[/tex]
Explanation:
Given
Magnitude of charge is [tex]q=0.5\ C[/tex]
Force experienced is [tex]F=20\ N[/tex]
Electric field intensity is the electrostatic force per unit charge
[tex]\therefore E=\dfrac{F}{q}\\\\\Rightarrow E=\dfrac{20}{0.50}\\\\\Rightarrow E=40\ N/C[/tex]
Thus, the electric field intensity is [tex]40\ N/C[/tex]
A motor is used to pump water from a depth of 5m to fill a volume of 10cubic meter in 5 min . If 50 percent of the power is wasted , What is the power of the motor?
For the mirror configuration below, the angle of incidence for the going towards the mirror on the right is 15 degrees. What is the angle of reflection for the light ray leaving the mirror on the bottom
Answer:
Thus, the angle of reflection is 15 degrees.
Explanation:
Angle of incidence, i = 15 degrees
The angle of incidence is the angle between the normal to the mirror and the incident ray, the angle of reflection is the angle between the reflected ray and the normal to the mirror.
According to the laws of reflection, the angle of incidence is equal to the angle of reflection.
Thus, the angle of reflection = angle of incidence = 15 degrees
After hearing about an accident on his normal route, Mr. Gujral checks for alternate routes to get to work. What type of circuit does this traffic situation model?
Answer:
C
Explanation:
a parallel circuit because there is more than one path
Answer:
C) a parallel circuit because there is more than one path
Explanation:
EDGE 2022
a volleyball player has spiked the ball. At the instant the ball leaves her hand, it is 2.6 m above the ground and has an initial vertical velocity of -20 m/s. How long will it take the ball to strike the ground if the opposing team doesn't block it?
Answer: 29.48 s
Explanation:
Given
The initial height of the ball is [tex]h=2.6\ m[/tex]
The ball leaves with an initial velocity of [tex]u=-20\ m/s[/tex]
Using the equation of motion
[tex]h=ut+\dfrac{1}{2}at^2\\\text{Insert the values}\\\\2.6=20\cdot t+\dfrac{1}{2}\times 9.8\times t^2\\\\\Rightarrow 9.8t^2+20t-5.2\\\\\Rightarrow t=\dfrac{-20\pm \sqrt{20^2-4\times 9.8\times (-5.2)}}{2\times 9.8}\\\\\Rightarrow t=\dfrac{-20\pm 603.84}{19.8}\\\\\Rightarrow t=29.48\ s\quad [\text{Neglecting negative t}][/tex]
Therefore, it take 29.48 s for ball to reach the ground.
The speed of light in a piece of plastic is 1.87 × 10^8 meters per second. What is the absolute index of refraction of this plastic?
Question 11 options:
1.00
1.6
0.67
1.33
[tex]\tt\red{See \; Your \: Answer!}[/tex]
Your answer was 0.67m...
In a plate glass factory, sheets of glass move along a conveyor belt at a speed of 15.3 cm/s. An automatic cutting tool descends at preset intervals to cut the glass to size. Since the assembly belt must keep moving at constant speed, the cutter is set to cut at an angle to compensate for the motion of the glass. The glass is 73.4 cm wide and the cutter moves from one edge to the other in 3.0 s. At what angle to the width of the sheet should the cutter be set to move?
n a plate glass factory, sheets of glass move along a conveyor belt at a speed of 15.3 cm/s. An automatic cutting tool descends at preset intervals to cut the glass to size. Since the assembly belt must keep moving at constant speed, the cutter is set to cut at an angle to compensate for the motion of the glass. The glass is 73.4 cm wide and the cutter moves from one edge to the other in 3.0 s. At what angle to the width of the sheet should the cutter be set to move
John and Henry push a piano with 800N, and the piano refuses to move. According to the definition of work in physics, there is NO work done on the piano.
Answer:
Explanation:
This is true because the definition of work is the parallel force required to move an object times the distance it moves. If it doesn't move, no work has been done. That is not to say that no energy has been expended, because it most certainly has! But that is not the same thing.
Do metals that react vigorously with hydrochloride acid also react vigorously with sulfuric acid?
Answer:
yes
Explanation:
Reactions of acids with metals
Acids react with most metals and, when they do, a salt is produced. But unlike the reaction between acids and bases, we do not get water. Instead we get hydrogen gas.
This is the general word equation for the reaction:
metal + acid → salt + hydrogen
For example, magnesium reacts with hydrochloric acid to produce magnesium chloride:
magnesium + hydrochloric acid → magnesium chloride + hydrogen
Mg + 2HCl → MgCl2 + H2
It doesn't matter which metal or which acid is used, if there is a reaction we always get hydrogen gas as well as the salt. However, how quickly the reaction goes depends on the metal used and how high up in the reactivity series it is.
Put these components from largest to smallest
1. comet
2. star
3. galaxy
4. nebula
5. planet
6. universe
Answer:
6, 3, 2, 5, 4, 1
Explanation:
Let's describe them from smallest to largest. In fact the size order is not exact as there are exceptions.
An asteroid is a rocky body which lies in the asteroid belt between Mars and Jupiter. They are typically quite small object. The largest asteroid Ceres has been reclassified as a dwarf planet.
A moon is typically a rocky body which is in orbit around a planet. Some moons such as our Moon are quite large and are typically bigger than asteroid. Some moons can actually be smaller than some asteroids.
A planet is a nearly spherical body which is in orbit around the Sun. Planets are larger than moons.
A star is what planets orbit around. It is the source of light and heat. Our Sun is a star which is many times bigger than all of the planets.
A solar system is a star and all of its planets, asteroids, comets and other bodies. It is significantly bigger than a star.
A galaxy, such as our Milky Way Galaxy, is a collection of solar systems orbiting around a central core. Most galaxies have a supermassive black hole at their centres.
Galaxies also form clusters which are large scale structures.
The universe is everything. It contains billions of galaxies.
A __________ is a push or pull.
Answer:
force
Explanation:
Force is a push or a pull of an object that causes the object to speed up, slow down, or stay in one place. In other words, a force is what causes an object to move. Friction and gravity are two types of forces that influence how an object moves.
A boat produces a wave as it passes an aluminum can floating in a lake. Explain why the can merely moves up and down while waves propagate away from the disturbance caused by the boat.
Answer:
Due to waves.
Explanation:
The can merely moves up and down because the movement of the waves that propagate away from the disturbance caused by the boat. The Can has low density due to low mass and high volume which allow the can to float on the surface of water after prevent it from the drowning. The wave moves the can up and down but prevent it from going deep inside the water so we can say that the can moves due to movement of waves in water.
Ohm's law states which relationship between electrical quantities? a. Volts = current x resistance b. Volts = current divided by amps c. Volts = coulombs divided by charge d. Volts = resistance times charge
Answer:
a. Volts = current x resistance
Explanation:
Ohm's law states that at constant temperature, the current flowing in an electrical circuit is directly proportional to the voltage applied across the two points and inversely proportional to the resistance in the electrical circuit.
Mathematically, Ohm's law is given by the formula;
[tex] V = IR[/tex]
Where;
V represents voltage measured in voltage.
I represents current measured in amperes.
R represents resistance measured in ohms.
Hence, Ohm's law gives the relationship between voltage, current and resistance of an electric circuit.
The diagram shows the electric field near conducting sphere a which of the following statements is correct
Make a free-body diagram of someone pushing a refrigerator that shows:
a. A net force of 100 N with the refrigerator being pushed to the right.
b. The refrigerator is balanced on the floor.
The free body diagram allows to find the results for the forces applied on the refrigerator are;
a) Free-body diagram with applied force.
b) Free-body diagram without applied force.
A free-body diagram is a diagram of the forces without the details of the body, these diagrams are important to clearly visualize the forces and the coordinate systems against which to take measurements.
In the attached we have a free-body diagrams for a refirerator, represented by the box where the forces are appreciated:
The weight that the forces exerted by the earth on the refrigerator. The Normal which is the reaction of the earth to the support of the refrigerator. The force applied by the person. The friction force which is the force between the two surfaces that opposes the movement of the refrigerator.
Newton's second law states that the net force is proportional to the mass times the acceleration of the body.
∑ F = ma
where F is the force, m the mass and the acceleration
∑ F = F - fr = 100 N
a = 100 / m
In conclusion with the free body diagram we can find the results for the forces applied on the refrigerator are;
a) Free-body diagram with applied force.
b) Free-body diagram without applied force.
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