How long does it take a car to cross a 20m bridge if it starts from rest and accelerates at 5 m/s^2?
2s
1.89s
1.41s
1.41 m
2.8s
Answers
The correct answer is 2.8s
Related Questions
a car starts from rest and drives at 45 m/s in 20 s. how far did it travel
Answers
Answer:
distance=speed×time.
45×20=900m.
A charge +Q is located at the origin and a second charge, +4Q, is at distance d on the x-axis. If a third charge, q, is placed somewhere, so that all three charges will be in equilibrium.1. What should be its sign, so that all three charges will be in equilibrium?A. Negative.B. Positive.2. What should be its magnitude, so that all three charges will be in equilibrium?
Answers
Answer:
Third charge should be placed at a distance d/3
Sign is negative
Magnitude is |q| = 4Q/3
Explanation:
To find a place where a third charge, q, is placed so that all three charges will be in equilibrium would be at;
E1 = E2
Now, let the distance between the charges +Q and +4Q be d. Also, let the distance from charge +Q to the third charge q be x.
Thus;
E1 = kQ/x²
E2 = k(4Q)/(d - x)²
Since equilibrium, then;
E1 = E2 gives;
kQ/x² = k(4Q)/(d - x)²
k and Q will cancel out to give;
1/x² = 4/(d - x)²
Cross multiply to get;
(d - x)² = 4x²
Taking square root of both sides gives;
√(d - x)² = √4x²
Gives;
d - x = 2x
d = x + 2x
d = 3x
x = d/3
This is the point at which E1 = E2.
Since at equilibrium, it means that Fq + F2 = 0
Now, electric force formula is;
F = kq1*q2/r²
So; Fq = kqQ/x²
F2 = kQ(4Q)/d²
Equating Fq + F2 = 0 gives;
kqQ/x² + kQ(4Q)/d² = 0
kqQ/x² = -kQ(4Q)/d²
Like terms cancel out to get;
q/x² = -4Q/d²
q = - 4Qx²/d²
earlier we saw that x = d/3.
So, q = -4Q × (d/3)²/d²
q = -4Q × ⅓
q = - 4Q/3
Thus,it's sign is negative.
It's magnitude will be the positive value.
Thus, magnitude is;
|q| = 4Q/3
1). The sign that will be of all the given three charges being in equilibrium would be:
A). Negative
2). The magnitude to allow all the given three charges to remain in equilibrium would be:
- Magnitude [tex]|q| = 4Q/3[/tex]
Given that,
First Charge [tex]= +Q[/tex]
Second Charge[tex]= +4Q[/tex]
Third Charge [tex]= q[/tex]
The location where they will be in equilibrium would be:
[tex]E1 = E2[/tex]
So,
We will assume the distance between the first two charges i.e. +Q and +4Q as d and assume the distance from charge +Q to the third charge q as x.
Now,
[tex]E1 = kQ/x^2[/tex]
[tex]E2 = k(4Q)/(d - x)^2[/tex]
Therefore,
The equilibrium will be at:
[tex]kQ/x^2 = k(4Q)/(d - x)^2[/tex]
by solving we get,
[tex]x = d/3[/tex]
Because at equilibrium [tex]Fq + F2 = 0[/tex],
So,
F [tex]= kq1*q2/r^2[/tex]
and [tex]Fq = kqQ/x^2[/tex]
[tex]F2 = kQ(4Q)/d^2[/tex]
by resolving the equation, we get;
[tex]Fq + F2 = 0[/tex]
[tex]kqQ/x^2 + kQ(4Q)/d^2 = 0[/tex]
By solving it, we get
[tex]Magnitude(q) = - 4Q/3[/tex]
Thus, the sign is negative.
and Magnitude |q| = 4Q/3
Thus, options A and [tex]|q| = 4Q/3[/tex] would be the correct answer.
Learn more about "Charge" here:
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A person driving a car suddenly applies the brakes. The car takes 7.0 s to come to rest while traveling 26 m at constant acceleration. What was the initial speed of the car (in m/s)?
Answers
Answer:
7.43 m/s
Explanation:
Time taken for car to stop = 7.0 s
distance traveled before coming to rest = 26 m
Final speed of the car = 0 m/s (since it stops)
initial speed of the car = ?
To get the final speed, we use the equation
s = [tex]\frac{1}{2}t(u + v)[/tex]
where
s is the distance traveled before stopping
u is the initial speed = ?
v is the final speed = 0 m/s
t is the time = 7 s
substituting values, we have
26 = [tex]\frac{1}{2}*7*(u + 0)[/tex]
26 = 3.5u
u = 26/3.5 = 7.43 m/s
A 20 kg block rests on a rough horizontal table. A rope is attatched to the block and is pulled with a force of 80 N to the left. As a result, the block accelerates at 2.5 m/s^2 . The coefficient is Kinetic force friction between the block and the table is ____( Round to the nearest hundredth )
Answers
Given :
Mass of block , M = 20 kg .
Force applied , F = 80 N .
Acceleration of block , [tex]a=2.5\ m/s^2[/tex] .
To Find :
The coefficient is Kinetic force friction between the block and the table .
Solution :
We know , Force equation on block is given by :
[tex]F_{net }=F-\mu_k mg \\\\ma = F-\mu_k mg \\\\20\times 2.5 = 80 -\mu_k \times 20 \times 10\\\\\mu_k\times 200=30\\\\\mu_k=\dfrac{30}{200}\\\\\ mu_k=0.15[/tex]
Therefore , coefficient is Kinetic force friction between the block and the table is 0.15 .
Hence , this is the required solution .
I want to know if high school starts hard and gets easier as the year goes? in your opinion
Answers
Answer:
It depends on how much you stress I recommend starting calm!
Explanation:
Answer:
I'm a senior right now, but I think the subjects gradually get more difficult, it's not all too difficult though, it's just stressful because the amount of work your expected to finish.
Explanation:
What is the difference between centrifugal force and centripetal force???
Answers
Answer:
Centripetal force is the force that is necessary to keep an object moving in a curved path and that is directed inward toward the center of rotation, while centrifugal force is the apparent force that is felt by an object moving in a curved path that acts outwardly away from the center of rotation
Explanation:
Hope this helps!
Brainliest if correct pls
Which of the following is an example of an electromagnetic wave? (2 points)
Red light
Ocean waves
Sound waves
Earthquakes
Answers
red lights are an example of an electromagnetic wave. visible lights are the only electromagnetic waves we can actually see on the spectrum. red, in particular has the biggest wavelength.
b) ocean waves
ocean waves are not an electromagnetic wave. in fact, it’s a mechanical wave. electromagnetic waves can travel through a vacuum, that is empty space, but mechanical waves cannot.
c) sound waves
sound waves are also not an electromagnetic wave. it’s a mechanical wave. you cannot hear electromagnetic waves.
d) earthquakes
an earthquake is also not an example of electromagnetic waves. it’s a mechanical wave.
hope this helps!
Answer:
a
Explanation:
2. What is the difference between distance and displacement?
Answers
Answer:
Distance is a scalar quantity that refers to "how much ground an object has covered" during its motion. Displacement is a vector quantity that refers to "how far out of place an object is"; it is the object's overall change in position.
Explanation:
:)
Answer: The complete length of the path between any two points is called distance. Displacement is the direct length between any two points when measured along the minimum path between them.
Explanation: It's what's!!
what are fossil fuels?
Answers
Answer:
Fossil Fuels are natural fuels like coal or gas that were formed millions of years ago and take millions of years to form. They are formed from the remains of past living organisms.
Explanation:
Well you do no really need an explanation for this one...
In a college of exactly 2560 students, exactly 50 % are male. What is the number of female students?
Answers
write down formula of power
Answers
Answer:
Power is a measure of the amount of work that can be done in a given amount of time. So, the formula is the energy or work divided by time:
P = W ÷ T, where p is power , w is work and t is time.
Plz help me this question is hard to under stand
Answers
Answer:
____________
in real world conditions?
it seems the most plausible.
Answer (B)
Cars are tested on closed tracks and race tracks so rule out A, D. Tha leaves us with B, C. C is kind of a real-world situation so the answer is most likely, B.
5. What is the velocity of a Nolan Catholic football player if he runs 200.0 m in 24.0 s?
Answers
Answer:
[tex] \boxed{ \bold{ \huge{ \boxed {\sf{8.33 \: m \:/s \: }}}}} [/tex]
Explanation:
Distance travelled = 200 metre
Time taken = 24 second
Velocity = ?
Finding the velocity
[tex] \boxed{ \sf{velocity = \frac{distance \: travelled \: }{time \: taken}}} [/tex]
[tex] \dashrightarrow{ \sf{velocity = \frac{200 \: m}{24 \: s} }}[/tex]
[tex] \dashrightarrow{ \sf{velocity = 8.33 \: m/s}}[/tex]
Hope I helped!
Best regards!
Convert 543 g to kg (Use correct number of significant figures for answer).
a
Ob
e
0.5 kg
0.54 kg
0.543 kg
5.0 kg
5.4 kg
5.43 kg
54,300 kg
543,000 kg
None are Correct
g
Answers
Answer:
0.543 kilogram
Explanation:
thats the answer
What happens when sulfur reacts with potassium?
Answers
Plz help me I will mark brainlieat Ques. Write down name and molecular formula of a
Compound which gives hydrogen ion and sulphate on
in solution state. In which colour is the methyl Orange
changed after treating with this compound? Why?
Write name of salt when the same compound is
treated with sodium hydroxide Write down chemical
equation
Answers
H2SO4 + NaOH —> 2H2O (aq.) + Na2SO4 (salt)
The resulted salt/compound (Na2SO4) when reacting with Methyl Orange (MO) is called ”Removal of methyl orange dye and Na2SO4 salt from synthetic wastewater using reverse osmosis (RO)”
The efficiency of reverse osmosis (RO) membranes used for treatment of colored water effluents can be affected by the presence of both salt and dyes.
Concentration polarization of each of the dye and the salt and the possibility of a dynamic membrane formed by the concentrated dye can affect the performance of the RO membrane.
The objective of the current work was to study the effect of varying the Na2SO4 salt and methyl orange (MO) dye concentrations on the performance of a spiral wound polyamide membrane.
The work also involved the development of a theoretical model based on the solution diffusion (SD) mass transport theory that takes into consideration a pressure dependent dynamic membrane resistance as well as both salt and dye concentration polarizations.
Control tests were performed using distilled water, dye/water and salt/water feeds to determine the parameters for the model.
The experimental results showed that increasing the dye concentration from 500 to 1000 ppm resulted in a decrease in the salt rejection at all of the operating pressures and for both feed salt concentrations of 5000 and 10,000 ppm.
Increasing the salt concentration from 5000 to 10,000 ppm resulted in a slight decrease in the percent dye removal. The model’s results agreed well with these general trends.
A roadrunner at rest suddenly spots a rattlesnake slithering directly away at a constant speed of 0.75 m/s. At the moment the snake is 10. Meters from the bird, the roadrunner starts chasing it with a constant acceleration of 1.0 m/s^2. How long will it take the roadrunner to catch up to the snake?
Answers
Answer:
The roadrunner will take approximately 5.285 seconds to catch up to the rattlesnake.
Explanation:
From the statement we notice that:
1) Rattlesnake moves a constant speed ([tex]v_{S} = 0.75\,\frac{m}{s}[/tex]), whereas the roadrunner accelerates uniformly from rest. ([tex]v_{o, R} = 0\,\frac{m}{s}[/tex], [tex]a = 1\,\frac{m}{s^{2}}[/tex])
2) Initial distance between the roadrunner and rattlesnake is 10 meters. ([tex]x_{o, R} = 0\,m[/tex], [tex]x_{o,S} = 10\,m[/tex])
3) The roadrunner catches up to the snake at the end. ([tex]x_{S} = x_{R}[/tex])
Now we construct kinematic expression for each animal:
Rattlesnake
[tex]x_{S} = x_{o,S}+v_{S}\cdot t[/tex]
Where:
[tex]x_{o, S}[/tex] - Initial position of the rattlesnake, measured in meters.
[tex]x_{S}[/tex] - Final position of the rattlesnake, measured in meters.
[tex]v_{S}[/tex] - Speed of the rattlesnake, measured in meters per second.
[tex]t[/tex] - Time, measured in seconds.
Roadrunner
[tex]x_{R} = x_{o,R} +v_{o,R}\cdot t +\frac{1}{2}\cdot a\cdot t^{2}[/tex]
Where:
[tex]x_{o, R}[/tex] - Initial position of the roadrunner, measured in meters.
[tex]x_{R}[/tex] - Final position of the roadrunner, measured in meters.
[tex]v_{o,R}[/tex] - Initial speed of the roadrunner, measured in meters per second.
[tex]a[/tex] - Acceleration of the roadrunner, measured in meters per square second.
[tex]t[/tex] - Time, measured in seconds.
By eliminating the final positions of both creatures, we get the resulting quadratic function:
[tex]x_{o,S}+v_{S}\cdot t = x_{o,R}+v_{o,R}\cdot t +\frac{1}{2}\cdot a \cdot t^{2}[/tex]
[tex]\frac{1}{2}\cdot a \cdot t^{2} + (v_{o,R}-v_{S})\cdot t + (x_{o,R}-x_{o,S}) = 0[/tex]
If we know that [tex]a = 1\,\frac{m}{s^{2}}[/tex], [tex]v_{o, R} = 0\,\frac{m}{s}[/tex], [tex]v_{S} = 0.75\,\frac{m}{s}[/tex], [tex]x_{o, R} = 0\,m[/tex] and [tex]x_{o,S} = 10\,m[/tex], the resulting expression is:
[tex]0.5\cdot t^{2}-0.75\cdot t -10=0[/tex]
We can find its root via Quadratic Formula:
[tex]t_{1,2} = \frac{-(-0.75)\pm \sqrt{(-0.75)^{2}-4\cdot (0.5)\cdot (-10)}}{2\cdot (0.5)}[/tex]
[tex]t_{1,2} = \frac{3}{4}\pm \frac{\sqrt{329}}{4}[/tex]
Roots are [tex]t_{1} \approx 5.285\,s[/tex] and [tex]t_{2}\approx -3.785\,s[/tex], respectively. Both are valid mathematically, but only the first one is valid physically. Hence, the roadrunner will take approximately 5.285 seconds to catch up to the rattlesnake.
Which of the following is an example of a chemical property? Density Solubility Flammability Magnetism
Answers
Answer:
Hey there!
Flammability is a chemical property. It doesn't change based on what state of matter the object is in.
Let me know if this helps :)
Answer:Flamibilliety
Explanation:
a current of 5 ampere is passed for 2 hours in an electric iron having a resistance of 100 ohms calculate the heat produced
Answers
Answer:
[tex] \boxed{\sf Heat \ produced \ (H) = 5 \ kWh} [/tex]
Given:
Resistance (R) = 100 Ω
Current (I) = 5 A
Time (t) = 2 hours
To Find:
Heat developed (H) in the electric iron
Explanation:
Formula:
[tex] \boxed{ \bold{ \sf H = I^2Rt}}[/tex]
Substituting values of I, R & t in the equation:
[tex] \sf \implies H = {5}^{2} \times 100 \times 2 \\ \\ \sf \implies H = 25 \times 100 \times 2 \\ \\ \sf \implies H = 5000 \\ \\ \sf \implies H = 5 \: kWh [/tex]
[tex] \therefore[/tex]
Heat developed (H) in the electric iron = 15 kWh
find the potential energy of a diver of mass 75kg at a height of 10m above a swimming pool g=9.8m
Answers
Answer:
[tex] \boxed{\sf Potential \ energy \ (PE) = 7.35 \ kJ} [/tex]
Given:
Mass (m) = 75 kg
Height (h) = 10 m
Acceleration due to gravity (g) = 9.8 m/s²
To Find:
Potential Energy (PE)
Explanation:
The formula for potential energy due to gravity:
[tex] \boxed{ \bold{PE = mgh}}[/tex]
Substituting value of m, g & h in the formula:
[tex] \sf \implies PE = 75 \times 10 \times 9.8 \\ \\ \sf \implies PE = 7350 \: J \\ \\ \sf \implies PE = 7.35 \: kJ[/tex]
help pls!!
acceleration:
a) the rate of change of position
b) acceleration caused by the force of gravitation
c) the rate of change in velocity; speeding up, slowing down, or changing direction
d) for every action force, there is an equal and opposite reaction force
Answers
Answer:C.
Explanation:
The rate of change in velocity; speeding up, slowing down, or changing direction
which type of mixture is air explain
Answers
Answer:Three elements make up over 99.9 percent of the composition of dry air: these are nitrogen, oxygen, and argon.
Explanation:
Answer: Air is an gaseous substance
Explanation:
Air is a homogeneous mixture of the gaseous substances nitrogen, oxygen, and smaller amounts of other substances. Salt, sugar, and many other substances dissolve in water to form homogeneous mixtures.
A race car speeds up with an acceleration of 10 m/s2 for 21 s. If its final velocity is 210 m/s, find its initial velocity.
Answers
Answer:
answer is 0m/ sec
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True or false: We still use the republican calendar created by the French.
Answers
Identify the term used to describe the number of protons and neutrons that are present in an atomic
nucleus.
Answers
Atomic mass
Explanation:
The unit for measuring protons and neutrons are called atomic mass. They weigh around the same thing.
This means divide or to take apart the pieces. ( science )
Answers
Answer:
disassemble, break apart,divide, separate
Explanation:
just know and have learned it....
Which statement describes an advantage of models? Models can be used to communicate and test designs ideas. Models always show the exact size of a system. Models have the ability to develop into complex systems. Models are useful for developing scientific methods.
Answers
Answer:
Models are useful for developing scientific methods.
Explanation:
Which statement describes an advantage of models? And Developing is an advantage of a model.
Developing scientific methods.
What are scientific methods?
"The scientific method is a process for experimentation that is used to explore observations and answer questions."
The scientific method has five basic steps, plus one feedback step:
Make an observation.Ask a question.Form a hypothesis, or testable explanation.Make a prediction based on the hypothesis.Test the prediction.Iterate: use the results to make new hypotheses or predictions.
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How many significant figures does the value 0.080 have?
Answers
When writing a number in scientific notation, how many digits should be to
the left of the decimal point?
o
A. None
B. One
C. Two
D. It depends on how precise you want your answer to be.
Answers
Answer:
C
Explanation:
1 point
In a biology experiment the number of yeast cells is determined after 24
hours of growth at different temperatures. What is the INDEPENDENT
variable? *
type of yeast
24 hour time period
different temperatures
number of yeast cells
Answers
Answer:
different temperatures
Explanation:
The independent variable would be different temperatures.
The independent variable is the variable that is manipulated or varied in an experiment in order to see the effects it will produce on another variable - the dependent variable. The values of the independent variable are directly inputted by the researcher and are not changed by any other variable throughout the experiment.
In the illustration, the effect of a variation in temperature is determined by counting the number of yeast cells. This showed that the manipulated variable is the temperature and hence, the independent variable.