Answer:
the object has decreasing acceleration and increasing velocity
Why is a device never 100% efficient? *
a) Mechanical Advantage
b) Work
c) Friction
d) Speed Ratio
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for science lovers!!
Which diagram is the best model for a solid ?
As a charged object approaches a neutral object the objects.......
attract
spin
repel
no interaction
Answer:
attract is the answer.
Answer:
It attracts
Explanation:
It attracts the object
Help.
Why do scientists believe that global warming is happening?
6. The peak value of an AC sine wave is
120 V. What's the effective value
(rounded)?
A. 65 V
B. 85 V
C. 200 V
D. 140 V
Answer:
B. 85 V
Explanation:
E(rms) = E(peak-to-peak) / squareroot(2)
E(rms) = 120V / 1.414 = 84.9 V
(When rounded) = 85 V
The correct option about peak value and effective value of AC sine wave is, “85 V”.
What are the differentiating factors between peak value and effective value?Peak value is also known as maximum value.Effective value is also known as RMS (Root Mean Square) value.Maximum value attained by Alternating quantity is defined as Peak value.The square root of average of the square of quantity during a complete cycle is defined as Effective Value. How to do the conversion between peak value and effective value?To convert peak value to effective value, divide the peak value by √2 and the result will be the effective value.To convert effective value to peak value, multiply the effective value with √2 and the result will be the peak value.How to solve this question?Peak value = 120 V (Given)
Effective value = Peak value ÷ √2
Effective value = 120 ÷ √2
Effective value = 85 V (approximately)
Thus, we can conclude that by dividing the peak value by √2, we will get effective value and multiplying the effective value with √2 will give peak value as result.
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What protects you from getting a shock when you touch a live wire?
A grounding wire
B circuit breaker
C fuse
D insulation
Answer:
Insulation protects you. Thats because the insulation will make a wall almost where the electrons cannot travel through. So when you touch the insulation on a live wire your SAFE. Insulations may include rubber, wood, and air.
Answer:
I'm pretty sure its insulation
Explanation:
why does a bouncing ball have a greater change in momentum than a ball that is just caught
If the ball bounces, then there is an additional velocity change sending the ball back upwards opposite the original direction. Thus, for the same collision time, bouncing involves a greater velocity change, a greater momentum change, and therefore a greater impulse.
Answer:
because with the change in momentum the velocity goes to zero. (more info below)
Explanation:
Momentum is the velocity change multiplied by the mass. When you think about it, bouncing an object means it comes back from anything it bounced against, giving it a velocity that is negative. This means that the velocity change for bouncing is greater than for colliding, as the velocity goes to zero in an inelastic collision like the one described.
hope this helped!
A large force will cause_______ acceleration than a small force
Answer:
A large force will produce more acceleration than a small force acting on the same object.
M
An object has a mass of 5.52 g and a volume of 12 mL. What is the density of the object
Answer:
0.46 g/mL
Explanation:
Density can be found using the following formula.
[tex]d=\frac{m}{v}[/tex]
where d is density, m is mass, and v is volume.
We know that the object has a mass of 5.52 grams and a volume of 12 milliliters.
m=5.52 g
v=12 mL
Substitute these values into the formula.
[tex]d=\frac{5.52 g}{12 mL}[/tex]
Divide 5.52 by 12
5.52/12=0.46
d=0.46 g/mL
The density of the object is 0.46 g/mL, and option C is correct.
7. How does friction affect the kinetic energy of an object?
Answer:
Friction is a resistive force to motion. When two bodies move against each other some of the kinetic energy is converted to heat energy due to friction. This reduces the total kinetic energy in the system. ... Mechanical energy is reduced due to friction and converted to heat.
Explanation:
Kinetic friction does oppose the relative motion of two surfaces. If the one of these surfaces is stationary, then it will tend to slow down the moving object.
Which situation will the lowest resistance occur
The correct choice is ' C '.
-- Shorter wire has less resistance than longer wire.
-- Thicker wire has less resistance than thinner wire.
-- Colder wire has less resistance than hotter wire.
____ charges are attract each other
Answer:
One positive and one negative
Which best describes Earth’s magnetic field lines? The field lines go out of Earth near the South Pole, enter Earth in the North Pole, and are aligned with the geographic poles. The field lines go out of Earth near the South Pole, enter Earth in the North Pole, and are not aligned with the geographic poles. The field lines go out of Earth near the North Pole, enter Earth in the South Pole, and are aligned with the geographic poles. The field lines go out of Earth near the North Pole, enter Earth in the South Pole, and are not aligned with the geographic poles.
Answer:
b
Explanation:
did the quiz
Answer:
(B) The field lines go out of Earth near the South Pole, enter Earth in the North Pole, and are not aligned with the geographic poles.
Explanation:
A circuit has a voltage drop of 12 V across a 30 2 resistor that carries a
current of 0.8 A. How much power is used by the resistor? Use P = VI.
A. 360 W
B. 12W
C. 9.6 W
D. 24 W
Answer:
C
Explanation:
V=12v
I=0.8A
P=VI
=(12)(0.8)
=9.6W
Answer:
9.6
Explanation:
How do you represent an object in a free body diagram?
A)An object is represented in a free-body diagram by an arrow and tail.
B)An object is represented in a free-body diagram by a box with a dot in
the middle, indicating its center of mass.
C)An object is represented in a free-body diagram by a word that says object.
D)An object is represented in a free-body diagram by having the mass labeled.
Clear answer
Answer: the answer is D
Explanation:
how does the direction of acceleration compare with the direction of the net force that produces it
Answer:
Explanation:
The direction of the acceleration is in the same direction as the net force causing it. F = ma is actually a vector equation in which f and a are both vectors and m is a scalar constant.
What is the velocity of the objects position vs time graph
Answer: In a position-time graph, the velocity of the moving object is represented by the slope, or steepness, of the graph line. If the graph line is horizontal, like the line after time = 5 seconds in Graph 2 in the Figure below, then the slope is zero and so is the velocity. The position of the object is not changing
Electron are _____ charged particles
Answer:
negatively
Explanation:
hope this can help u :3
Answer:
negatively
Explanation:
6. How is work related to kinetic energy?
Answer: Energy should be transferred to an object in order to move it. This amount of energy transferred by the force to move an object is called work or work done. Thus, the relation between Work and Energy is direct. That is, the difference in the Kinetic energy of an object is work done by an object. OR
The principle of work and kinetic energy (also known as the work-energy theorem) states that the work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle. The kinetic energy of the block increases as a result by the amount of work.
Explanation:
What will happen if a circular coil is used instead of a rectangular coil as the conducting coil in a generator?
Explanation:
when we use our circular coil, the magnetic field will always be perpendicular to the area vector.thus, due to this, sin wt gives sin 90 degree and that gives 1, giving maximum linking of flux associated with the coil at any position .
Answer:
When we use a circular coil, the magnetic field will always be perpendicular to the area vector. Thus, due to this, sinωt gives sin90∘ and that gives 1 , giving maximum linking of flux associated with the coil at any position.
Explanation:
4. How does a molecule differ from an atom? (4 points)
An electron in a mercury atom drops from energy level f to energy level c by emitting a photon having an energy of
1. 8.20eV
2. 5.52eV
3. 2.84eV
4. 2.68eV
Answer:
The answer is 2.84 eV
Explanation:
An electron in a mercury atom drops from energy level f to energy level c by emitting a photon having an energy of 2.84eV.
What is mercury?Mercury is known to be a type of naturally-occurring chemical element that has been discovered in rock that is found in the earth's crust.
They can be found as a form of deposits of coal. On the periodic table, it symbol is "Hg" and it has about 80 atoms. It can be found as Elemental (metallic) mercury, Inorganic mercury compounds, etc.
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A lens with f= 10.0 cm is held
45.0 cm from an object. What is
the image distance?
(Unit = cm)
it is not 12 cm.
Answer:
8.2 cm
Explanation:
1/f = 1/so + 1/si
1/10 = 1/45 + 1/si
1/si = 1/10 - 1/45
1/si = 9/90 - 2/90
1/si = 7/90
si = 90/7 = 12.86 cm.
since you said that the answer was not 12 them the lens must be concave with negative (minus) focal length
1/f = 1/so + 1/si
- 1/10 = 1/45 + 1/si
1/si = - 1/10 - 1/45
1/si = -9/90 - 2/90
1/si = -11/90
si = -90/11 = - 8.2 cm
- (read: minus or negative sign) indicates the image is in the same side of the object
hope its true and can help you
Answer:
1/f = 1/u + 1/v
f=10cm
u=45cm
v=? (Image distance)
1/v = 1/f - 1/u
1/v = 1/10 - 1/45
1/v = (9-2)÷ 90
1/v = 7/90
:. v = 90/7
v=12.86cm(image distance)
If you see ##### in a cell, you should
make the row taller
retype the number
type in a different number
make the column wider
Answer:
it's D. Make the column wider
Explanation:
A model of an atom is useful when it
Select one:
O a. is shown only as the planetary model
b. shows exactly what an atom looks like
c. helps to visualize processes that cannot be seen with our eyes
d. magnifies what the eye can't see
A mover uses a ramp to load a crate of nails onto a truck. The crate, which must be lifted 1.5 m from the street to the bed of the truck, is pushed along the length of the ramp. If the ramp is 4.5 m long and friction between the ramp and crate can be ignored, what is the mechanical advantage of the ramp?
Answer: M.A = 3
Explanation:
A ramp is an example of an inclined plain. Where the
Height H = 1.5 m
Length L = 4.5 m
Mechanical advantage of a machine is the ratio of the load to effort. While mechanical advantage M.A of an inclined plain is the ratio of the length of the plain to the height of the plain.
M.A = L/H
Substitute the values of L and H into the formula
M.A = 4.5/1.5 = 3
The mechanical advantage of the ramp is 3
What scientific evidence supports the Big Bang theory?
Universe expansion
Redshift
Composition of the universe
All of the above
None of the above
Answer:A universe expansion
Explanation:
The earliest and most direct observational evidence of the validity of the theory are the expansion of the universe according to Hubble's law (as indicated by the redshifts of galaxies), discovery and measurement of the cosmic microwave background and the relative abundances of light elements produced by BBN.
What happens to the average kinetic energy of water molecules as water freezes
A. It increases as the water releases energy to its surroundings
B. It increases as the water absorbs energy from its surroundings
C. It decreases as the water releases energy to its surroundings
D It decreases as the water absorbs energy from its surroundings
Answer:
C. It decreases as the water releases energy to its surroundings
Explanation:
The energy that is possessed in the body because of the motion is said to be kinetic energy. When the water freezes, the kinetic energy of the water molecules decreases as the particles stop motion. The energy is released in the surrounding. Freezing takes place when the liquid molecules slow down and lose the kinetic energy to form the solid crystals.
1. Of the following, the one that is not an example of a suspension is
a. Milk
b. Milk of magnesia
c. Sand in water
d. Sugar in water
2. The word used to represent a chemical reaction is a/an
a. Atom
b. Formula
c. Equation
d. Symbol
3. When two similarly charged objects are brought close together, they
a. Repel each other
b. Have no effect on each other
c. Stick to each other
d. Attract each other
4. An element common to all acids is
a. Chlorine
b. Hydrogen
c. Nitrogen
d. Oxygen
5. Atoms of the same element that differ slightly in mass are called
a. Ions
b. Isotopes
c. Neutrons
d. Positrons
6. In general, salts
a. Contain hydroxide ions
b. Contain hydrogen ions
c. Are ionic compounds
d. Turn blue litmus red.
7. A dye used to test the acidity of a substance is
a. Litmus
b. Magnesium sulfate
c. Sodium chloride
d. Sodium hydroxide
8. The central portion of an atom is called the
a. Electron
b. Nucleus
c. Ring
d. Shell
9. Sugar is poured into a glass of water and stirred. In this example the sugar is the
a. Solution
b. Solvent
c. Solute
d. Alcohol
10. Which of the following is characterized by a sour taste?
a. Bases
b. Acids
c. Salts
d. Compounds
11. Which of the following is characterized by a bitter taste and turn lithmus blue?
a. Bases
b. Acids
c. Compounds
d. Elements
12. The force of gravity on an object is called
a. Density
b. Mass
c. Volume
d. Weight
13. The liquid referred to as the “universal solvent” is
a. Alcohol.
b. Benzene.
c. Oil.
d. Water.
14. A statement that proposes a cause-and-effect relationship between two variables is called:
a. Conclusion.
b. Fair test.
c. Hypothesis.
d. Theory
15. Any substance that has mass and occupies space is called
a. A gas
b. A liquid
c. Matter
d. A solid
16. When the numbers of electrons and protons in a sample of matter are equal, the matter is
a. Insulated.
b. Negatively charged.
c. Neutral.
d. Positively charged.
17. Which of the following is most important when judging the quality of a scientific theory?
a. The quality and reliability of data that support the theory
b. The amount of detail provided in the theory
c. How recently the theory has been published
d. The respectability of the scientists setting forth the theory
18. Substances that cannot be decomposed to any simpler substances are called
a. Compounds.
b. Elements.
c. Mixtures.
d. None of the above.
19. When the air in a bell jar containing a ringing bell is removed, the sound decreases because
a. The removal of the air prevents electric current from flowing
b. Sound cannot travel through the air
c. Sound cannot travel through glass
d. Sound cannot travel in a vacuum
20. An element common to all acids is
a. Chlorine.
b. Oxygen.
c. Nitrogen.
d. Hydrogen.
21. The amount of matter in an object is best expressed by its
a. Density
b. Mass
c. Volume
d. Weight
22. A substance that increases the rate of a reaction is a
a. Liquid
b. Gas
c. Catalyst
d. Solid
Answer: 1. C
Explanation: 2. C
A blow dryer transfers thermal energy mainly by
A. conduction
B. convection
C. radiation
D. specific heat
Answer:
B
Explanation:
Through air
Answer:
thermal conduction I assume
Explanation:
why because the thermal Insulator: a material that conducts thermal energy poorly. Gives off heat