Answer:
t= (20, 25, ... 40) s
Explanation:
This is an exercise in kinematics specifically of uniform motion, the first thing we must do is set a reference system, we place our zero in the police car, we write the equations
police car
x₁ = v₁ t
truck
x₂ = x₀ + v₂ t
In this case, they indicate several initial positions of the truck and the speed of the two vehicles, at the meeting point the positions must be the same
x₁ = x₂
v₁ t = x₀ + v₂ t
t (v₁ - v₂) = x₀
t = [tex]\frac{x_{o} }{v_{1}- v_{2} }[/tex]
let's calculate for each initial position
x₀ = 80m
t = 80 / (25-21)
t = 80/4
t = 20 s
x₀ = 100 m
t = 100/4
t = 25 s
the last x₀ = 160 m
t = 160/4
t = 40 s
we can see that the time increases as the distance between the vehicles increases
An elevator car has a mass of 750 kg, and its three passengers have a combined mass of 135 kg. If the elevator and its passengers ride to the ground floor, 20.7 m below, find the change in gravitational potential energy of the car and its passengers. Show all your work.
Answer:
The change in gravitational potential energy is -1.80x10⁵ J.
Explanation:
The change in gravitational potential energy is given by:
[tex] \Delta E_{p} = E_{p_{f}} - E_{p_{i}} [/tex]
[tex] \Delta E_{p} = mgh_{f} - mgh_{i} [/tex]
Where:
"i" is for final and "f" for final
m: is the mass
g: is the gravity = 9.81 m/s²
h: is the height
For the car and the passengers we have:
[tex] \Delta E_{p} = m_{T}g(h_{f} - h_{i}) = (750 kg + 135 kg)9.81 m/s^{2}(0 - 20.7 m) = -1.80 \cdot 10^{5} J [/tex]
The minus sign is because when the elevator car and the passengers are up they have a bigger gravitational potential energy than when they are in the ground.
Therefore, the change in gravitational potential energy is -1.80x10⁵ J.
I hope it helps you!
True or false? When a change of state starts to occur, the energy supplied changes the temperature but not the internal energy.
Answer:
True
Explanation:
This heat energy allows the change of state to happen, and the temperature remains constant during the process. The amount of energy required to change the state of a substance depends upon the mass and characteristics of that substance. The energy required to change the state of a material is known as the latent heat. During a change of phase the temperature does not change, but the internal energy does. The internal energy is the sum of the kinetic energy of the molecules and the chemical potential energy of the molecules.
The moon Phobos orbits Mars
(mass = 6.42 x 1023 kg) at a distance
of 9.38 x 106 m. What is its period of
orbit?
Skip
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-nte
Answer:
The moon Phobos orbits Mars
(mass = 6.42 x 1023 kg) at a distance
of 9.38 x 106 m. What is its period of
orbit?
Explanation:
Answer: 27.9816 x 10^3 is the period of orbit
At night, within how many feet of approaching a vehicle from the rear must you dim your high beam headlights
Answer: 500 ft
Explanation:
High beam headlights help one to see better at night as the range of vision is greatly expanded. They can however, blind drivers coming on the opposite lane.
It is therefore prudent to ensure that when using high beam headlights, you dim them when a car is coming towards you. The appropriate distance to do so is a minimum of 500 ft from the car.
help pls physics problem
Answer:
0.4329 seconds
Explanation:
We are given;
Distance; d = 0.635 m
Velocity; v = 3.22 m/s
Angle; θ = 62.9°
To find the time, we have to find the horizontal component of the velocity.
Thus, Vx = 3.22 × cos 62.9
Formula for time is;
t = d/Vx
t = 0.635/(3.22 × cos 62.9)
t = 0.4329 sec
Thus the time he will take to clear the hurdle is 0.4329 sec
How can speed and velocity be used to describe motion?
Answer:
speed described how fast the object moves velocity describes how fast and in what direction its moved..
acrostic poem for cell theory. Especially theory
Answer:
In biology, cell theory is the historic scientific theory, now universally accepted, that living organisms are made up of cells, that they are the basic structural/organizational unit of all organisms, and that all cells come from pre-existing cells. Cells are the basic unit of structure in all organisms and also the basic unit of reproduction.
Explanation:
The three tenets to the cell theory are as described below:
All living organisms are composed of one or more cells.
The cell is the basic unit of structure and organization in organisms.
Cells arise from pre-existing cells.
There is no universally accepted definition of life. Some biologists consider non-cellular entities such as viruses living organisms,[1] and thus reasonably disagree with the first tenet. Throughout this article, it will lead you through the history of cell theory, how the discovery of cells was made possible, what the cell theory has become today and background information and history regarding other opposing concepts of cell theory.
It has been known for many years that ceramics can conduct electricity. In 2008, scientists found a ceramic material that can conduct electricity with no resistance at 133 K. What is the most important significance of this 2008 finding?
This is a lower temperature than Onnes’s experiment, and it will allow for a broader use of superconductors.
This is a higher temperature than Onnes’s experiment, and it will allow for a broader use of superconductors.
Materials that can conduct electricity with no resistance are new and can allow for new materials to be made.
Ceramic materials have been known to be able to conduct electricity prior to year 2008.
Answer:
mercury
Explanation:
edge 2020
write the chemical name and chemical formula for four hydrogens and two nitrogen
Answer:
2 moles of H2Nsuperscript(-) or NHsubscript2 , amide group!
I hope it will be useful.
The point of a nail has an area of 0.25cm squared, and an average person has a weight of 700 N. Explain in detail why it is possible to lie on a bed of 4000 nails, but not on one single nail. Thanks
Answer:
It is possible to lie on a bed of 4000 nails, but not on one single nail because a bed of 4000 nails exerts lesser pressure than a bed of one single nail .
Explanation:
Given;
weight of an average person, W = F = 700 N
area of the nail, A = 0.25 cm² = 0.25 x 10⁻⁴ m²
The pressure exerted by a single nail is given as;
P = F / A
P = 700 / (0.25 x 10⁻⁴)
P = 2.8 x 10⁷ N/m²
The pressure exerted by 4000 nails is given as;
Total surface area of 4000 nails = 4000 x 0.25 x 10⁻⁴ m² = 0.1 m²
P = F / A
P = 700 / 0.1
P = 7,000 N / m²
From the calculated values, 4000 nails exerts less pressure on the person than one single nail because pressure decreases with increase in surface area of an object.
Thus, it is possible to lie on a bed of 4000 nails, but not on one single nail because a bed of 4000 nails exerts lesser pressure than a bed of one single nail .
Given the distance between the crest of one wave and the crest of the next wave, you can determine the?
Explain why can an object moves or remain
stationary if it has balanced forces acting on it
Answer:
A balanced force means that equal force is being applied to an object on opposite sides. If equal force is being applied, there will be no change in the motion of the object; it will remain stationary. A greater force needs to be applied to one side for movement to take place.
Explanation:
Hope this helps (づ｡ ◕‿‿◕｡) づ
Love ya
Which of these materials is not magnetic?'
*
Cobalt
Iron
Copper
Stainless Steel
Answer:
stainless steel is the material which is non magnetic.
Which object has a net force of -68 N?
F = 31 N
F = 89 N
F, = 27 N
F=-53N
F = 53 N F-56N
F = 103 N
F = 34 N
F=-102 N
F = -27 N
F = -74 N
F=-89 N
Answer:third one from the left
Explanation:
The third object from the given problem has a net force of - 68 Newtons because there is no net vertical force action of this object as equal upward and downward forces cancel each other.
What is Newton's second law?Newton's Second Law states that The resultant force acting on an object is proportional to the rate of change of momentum.
F = m*a
The net vertical force = 27 Newtons - 27 Newtons
= 0 Newtons
The net vertical force on the object would be zero.
The net horizontal force acting on the object = - 102 Newtons + 34 Newtons
= -68 Newtons
Hence we can conclude that the net force of - 68 Newton acting on the third object.
Learn more about Newton's second law here, refer to the link;
brainly.com/question/13447525
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How are computers used in education and entertainment? List them.
Answer:
The computers used in education and entertainment are:
Explanation:
Analog computer,Digital COMPUTER,Hybrid Computer
do all objects have inertia
a) true
b) false
Answer:
The answer is A. Which is true
A clock which has brass pendulum beats correctly at 30C will it run faster or slower if temperature increase or decrease
Answer:
We know that the period of a pendulum is written as:
T = 2*pi*√(L/g)
where:
g = gravitational acceleration = 9.8m/s^2
pi = 3.1415...
L = length of the pendulum, in this case, is the length of the brass pendulum.
Now, we know that the brass dilates when the temperature increases.
Then if the temperature increases, the value of L will increase, which means that the period T will also increase, because L is in the numerator of T.
If the period increases the complete motion of the pendulum needs more time, this would mean that the clock will run slower.
If the temperature decreases, the opposite occurs, the value of L decreases, and then the period also decreases, which means that the clock will run faster.
A 15-kilogram wagon originally at rest on a level road is pulled by a rope that exerts a constant horizontal force of 45 newton's, If the frictional forces on the wagon total 15 newton's, what will be its acceleration ? *
2.0 〖m/s〗^2
4.0 〖m/s〗^2
15 〖m/s〗^2
30 〖m/s〗^2
3.0 〖m/s〗^2
Answer:
A. 2 m/[tex]s^{2}[/tex]
Explanation:
Mass of wagon = 15 kg
Horizontal force = 45 N
frictional force = 15 N
It is good to note that part of the exerted horizontal force would be used to overcome the frictional force on the wagon.
So that, total force exerted on the wagon can be determined by;
total force = horizontal force - frictional force
= 45 - 15
= 30 N
From Newton's second law of motion, we have;
F = ma
Where: F is the force applied on an object, m is its mass, and a is the acceleration of the object.
Thus,
30 = 15 x a
a = [tex]\frac{30}{15}[/tex]
= 2 m/[tex]s^{2}[/tex]
The acceleration of the wagon is 2 m/[tex]s^{2}[/tex].
When a capacitor, in RC circuit, is fully charged, the current through the resistor is Select one: zero if it is the only capacitor, but maximum if there is another capacitor in series with it. At its maximum value. Greater than the current in a resistor that is farther from the battery than the capacitor. Zero. Equal to the current in a resistive circuit in parallel with the capacitor circuit.
Answer:
The correct option is "Zero". A further explanation is given below.
Explanation:
As we know,
The capacitor is given by:
⇒ [tex]Q=C\times V[/tex]
Rate of change with respect to the time will be:
⇒ [tex]\frac{dQ}{dt}=C\times \frac{dV}{dt}[/tex]
Now,
It is mentioned in the question that the capacitor is completely charged, then
⇒ [tex]\frac{dV}{dt}=0[/tex]
i.e.,
⇒ [tex]\frac{dQ}{dt}=0[/tex]
All other choices available aren't related to that same scenario in question. So the answer above is the perfect one.
Calculate the total energy transferred when 200 g of ice cubes at 0°C are changed to steam at 100°C.
Specific heat capacity of water = 4200 J/kg °C
Specific latent heat of fusion = 340 kJ/kg
Specific latent heat of vaporisation = 2260 kJ/kg
Answer:
[tex]604000\ \text{J}[/tex]
Explanation:
m = Mass of ice = 200 g
[tex]\Delta T[/tex] = Temperature change of water = [tex](100-0)^{\circ}\text{C}[/tex]
c = Specific heat capacity of water = 4200 J/kg °C
[tex]L_f[/tex] = Specific latent heat of fusion = 340 kJ/kg
[tex]L_v[/tex] = Specific latent heat of vaporisation = 2260 kJ/kg
Heat required to convert ice to water = [tex]mL_f[/tex]
Heat required to raise the temperature of water to boiling point = [tex]mc\Delta T[/tex]
Heat required to convert water to steam = [tex]mL_v[/tex]
Total heat required
[tex]q=mL_f+mc\Delta T+mL_v\\\Rightarrow q=m(L_f+c\Delta T+L_v)\\\Rightarrow q=0.2(340\times 10^3+4200(100-0)+2260\times 10^3)\\\Rightarrow q=604000\ \text{J}[/tex]
Heat required to convert the given amount of ice to steam at the required temperature is [tex]604000\ \text{J}[/tex].
Your older brother has been dealing in gold business brings to you a cube of a
stone of uniform sides and claims its gold. Having studied density, explain stating
all the instruments involved how you can affirm that the stone is gold.
Answer:
Explanation:
The density of gold is 19.3 g/cm³. Thus, you can determine the density of the unknown cube by doing the following. Get a measuring cylinder (marked in cm³) that contains a certain volume of water (preferably above average but not close to been filled up). Get a weighing balance (that can read in grams) also.
Measure the mass of the unknown stone (using the weighing balance) and record. Take the initial volume of the water in the measuring cylinder and record (in cm³) and then drop the unknown stone inside the measuring cylinder gently (avoid splashes). Record the final volume of the cylinder after the unknown stone was dropped.
Then calculate the density of the stone by using the formula; mass ÷ change in volume
The change in volume can be determined by; Final volume - initial volume
If the answer obtained from the calculation (of the density of the stone) is not around 19.3 g/cm³ (say 19.3 ± 0.2), then the stone is not gold but if it is around 19.3 g/cm³, then the stone is gold.
a communication satellite is stationed in an orbit high abovr the earth. which of the follwoing will not be exhibeted by communication satellites.
a) rotational motion and periodic motion
b) periodic motion and circular motion
c) rotational motion and rectilinear motion
d) periodic motion and oscillatory motion
i) A and B
ii) B and C
iii) A only
iv) D only
Pls help
Answer:
i think ii)
B and c
i'm note sure though
20 pts !!!!
Four identical pallets of bricks, each with a mass of 40 kg with a square cross-sectional area of 0.50 m2, are stacked on the floor. What is the change in height of the pallet at the bottom of the stack if the pallets are 5.0 m tall when not stacked?
a.
1.04 μm
b
0.78 μm
c
0.26 μm
d
0.16 μm
Find the direction cosines of cartesian coordinates (3, -1, 2).
Explanation:
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What is the motion of the particles in this kind of wave?
O The particles will move up and down over large areas.
O The partices will move up and down over small areas.
O The particles will move side to side over small areas.
O The particles will move side to side over large areas.
Answer:
a is correct
The particles will move up and down over large areas.
Answer:
B. The particles will move up and down over small areas.
Explanation:
I just took the quiz and got 100% :)
What are the units of Mass and Weight in the English System? Explain.
Answer:
I tried...
Explanation:
Assuming the English system of mass and weight is the same as the Imperial system, the measurements are:
• 1 pound (lb) = 16 ounces (oz)
• 2,000 pounds (lbs) = 1 ton (T)
I think that's everything?
In the English system, mass is measured in pounds and weight is also measured in pounds. However, it is important to understand the difference between mass and weight.
Mass is a measure of the amount of matter in an object and is a scalar quantity. It does not change with location or gravitational force. In the English system, mass is typically measured using a scale or balance, which compares the object's mass to a standard mass. The pound (lb.) is the unit of mass in the English system.
Weight, on the other hand, is a measure of the force exerted on an object due to gravity and is a vector quantity. It depends on the object's mass and the gravitational force acting on it. In the English system, weight is typically measured using a spring scale or a balance that incorporates a spring. The pound (lb.) is also used as the unit of weight in the English system.
Weight = Mass x Acceleration due to gravity
Mass is measured in pounds (lb.) and weight is also measured in pounds (lb.).It is important to note that weight can vary depending on the gravitational force acting on an object.
Learn more about weight here:
https://brainly.com/question/28221042
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What is the kinetic energy of a go-kart with a mass of 25 kg and a velocity of 2 m/s?
Answer:
50 JExplanation:
The kinetic energy of an object can be found by using the formula
[tex]k = \frac{1}{2} m {v}^{2} \\ [/tex]
m is the mass
v is the velocity
From the question we have
[tex]k = \frac{1}{2} \times 25 \times {2}^{2} \\ = 12.5 \times 4[/tex]
We have the final answer as
50 JHope this helps you
Name ten scalar quantity and explain them
Answer:
A scalar is a quantity that is fully described by a magnitude only. It is described by just a single number. Some examples of scalar quantities include speed, volume, mass, temperature, power, energy, and time.
Examples of scalar quantity are:
Distance.
Speed.
Mass.
Temperature.
Energy.
Work.
Volume.
Area.
Explanation:
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how can you verify the archimedes principle?
Answer:
It is found that W1 - W2 loss in weight of solid when immersed in water is equal to the weight of the water displaced by the body. This verifies Archimedes' principle.