in an effort to reach the store before it closed the motorist increase the speed of his car from 20 m per second to 60 meters per second over a four second. What was the car's acceleration
Answer:
10
Explanation:
Givens
vi = 20 m/s
vf = 60 m/s
t = 4 second.
Formula
a = (vf - vi) / t
a = (60 - 20)/4
a = 40 / 4
a = 10 m/s^2
Which Newton’s law is shown below?
First
Second
Third
Pls answer
Answer:
This is Newton's first law.
Explanation:
An object in motion will stay in motion and an object at rest wI'll stay at rest unless acted upon by an unbalanced force.
You are riding a skateboard and hit a hole in the street, causing you to fly off the board and crash. Which law represents this action? *
Answer:
Newton's first law of motion states that an object at rest will remain at rest and an object in motion will remain in motion unless it is acted on by an unbalanced force. Using unbalanced forces to control the motion of a skateboard demonstrates Newton's first law of motion.
Hope it helps
Answer:
Good question! It's the law of motion.
Explanation:
A whistle emitting a note of 4 kHz is
whirled in a horizontal circle of radius 1 m at a constant speed. If the highest note heard
by a person a large distance away is 4200 Hz, find:
(i) the speed of the whistle
(ii) the lowest note heard by the person,
(iii) the time taken for the whistle to make on complete revolution,
(iv) the time interval between the person hearing the highest and lowest note.
Answer:
(i) The speed of the whistle is 16.[tex]\overline 3[/tex] m/s
(ii) The lowest note heard by the person is 3,818.[tex]\overline{18}[/tex] Hz
(iii) The time taken for the whistle to make one revolution is approximately 0.38468 seconds
(iv) The time interval between the person hearing the highest and lowest note is approximately 0.19234 seconds
Explanation:
The question relates to the Doppler effect for which the change in frequency is given as follows;
[tex]f_L = \left ( \dfrac{v \pm v_L }{v \pm v_S} \right ) \cdot f_S[/tex]
Where;
[tex]f_L[/tex] = The frequency heard by the listener
v = The speed of sound in air = 343 m/s
[tex]v_L[/tex] = The listener's speed
[tex]v_S[/tex] = The source's (whistle) speed
[tex]f_S[/tex] = The frequency of the source
The given parameters are;
The frequency of the whistle (source), [tex]f_S[/tex] = 4 kHz = 4,000 Hz
The radius of the horizontal circle around which the whistle is whirled = 1 m
The highest note heard by a person a large distance away = 4200 Hz
The distant listener is taken as stationary, [tex]v_L[/tex] = 0 m/s
We therefore have;
[tex]f_L = \left ( \dfrac{v \pm 0 }{v \pm v_S} \right ) \cdot f_S = \left ( \dfrac{v }{v \pm v_S} \right ) \cdot f_S[/tex]
(i) When the whistle's motion while it is being whirled towards the listener, [tex]v_S[/tex] is negative
When the whistle's motion while it is being whirled is away from listener, [tex]v_S[/tex] is positive
The highest note, [tex]f_{LH}[/tex], is obtained with the lowest denominator, that is when the source moves towards the listener and [tex]v_S[/tex] is negative, we get;
[tex]f_{LH} = 4,200 \ Hz = \left ( \dfrac{343 \ m/s }{343 \ m/s - v_S} \right ) \times 4,000 \ Hz[/tex]
[tex]\dfrac{4,200 \ Hz}{4,000 \ Hz} = \dfrac{21}{20} = \dfrac{343 \ m/s}{343 \ m/s - v_S}[/tex]
21·(343 m/s - [tex]v_S[/tex]) = 20×343 m/s
21 × [tex]v_S[/tex] = 21 × 343 m/s - 20 × 343 m/s = 343 m/s
[tex]v_S[/tex] = (343 m/s)/21 = 49/3 m/s = 16.[tex]\overline 3[/tex] m/s
The speed of the source = The speed of the whistle
∴ The speed of the source = [tex]v_S[/tex] = 16.[tex]\overline 3[/tex] m/s = The speed of the whistle
(ii) The lowest note heard by the person occurs when the denominator of the formula for the change in frequency is smallest for which we have the value of [tex]v_S[/tex] as positive and the source moves away from the observer which is presented as follows;
[tex]f_{LH} = \left ( \dfrac{343 \ m/s }{343 \ m/s +16.\overline 3 \ m/s } \right ) \times 4,000 \ Hz = 3,818.\overline {18} \ Hz[/tex]
The lowest note heard by the person = 3,818.[tex]\overline{18}[/tex] Hz
(iii) The angular velocity of the whistle, ω is given as follows;
[tex]\omega = \dfrac{\theta}{t} = \dfrac{v_S}{r} = \dfrac{16. \overline 3 \ m/s}{1 \ m} = 16. \overline 3 \ radians/second[/tex]
The angle rotated in one revolution, is 2·π radians, therefore, when θ = 2·π radians, the time, [tex]t_c[/tex], to complete one revolution is given as follows;
[tex]t_c = \dfrac{\theta}{\omega} = \dfrac{2 \times \pi \ radians}{16. \overline 3 \ radians/second} \approx 0.385 \ seconds[/tex]
Therefore, the time to complete one revolution ≈ 0.38468 seconds
(iv) The time interval between the person hearing the highest and lowest note is the time to complete half a cycle ≈ 0.38468/2 seconds ≈ 0.19234 seconds.
Calculate the magnitude and direction of a vector whose x and y components are given
to be 30 and 40 units respectively.
Answer:
Magnitude = 50 units
Direction = 53.13°
Explanation:
The formula to find out the magnitude of a resultant vector with the help of its x and y components is given as follows:
[tex]Magnitude = \sqrt{x^{2} + y^{2}}\\\\[/tex]
where,
x = 30 units
y = 40 units
Therefore,
[tex]Magnitude = \sqrt{(30 unit)^{2} + (40\ unit)^{2}}\\\\[/tex]
Magnitude = 50 units
Now, the direction of the resultant vector will be given by the following formula:
[tex]Direction = tan^{-1}\frac{y}{x}\\\\Direction = tan^{-1}\frac{40}{30}[/tex]
Direction = 53.13°
help me please!!!!!..............
Answer:
The car took 3 hours to travel 180 miles
Explanation:
Constant Speed Motion
An object travels at constant speed if the ratio of the distance traveled by the time taken is constant.
Expressed in a simple equation, we have:
[tex]\displaystyle v=\frac{d}{t}[/tex]
Where
v = Speed of the object
d = Distance traveled
t = Time taken to travel d.
From the equation above, we can solve for t:
[tex]\displaystyle t=\frac{d}{v}[/tex]
The car travels at v=60 mi/h for a distance of d=180 miles. The time taken is:
[tex]\displaystyle t=\frac{180\ mi}{60\ mi/h}[/tex]
t = 3 hours
The car took 3 hours to travel 180 miles
Pollen grains help scientists
identify plants and make assumptions on past climate conditions.
understand tree growth and make assumptions on past climate conditions.
understand how Earth was shaped and make assumptions on past climate conditions.
identify major ice ages and make assumptions on past climate conditions.
Answer:
A. identify plants and make assumptions on past climate conditions.
Explanation:
Answer was right on my Edge quiz!
Pollen grains help scientists identify plants and make assumptions on past climate conditions.
WHAT IS PROXY CLIMATE?Proxy climate is climate inferred from past records i.e. not current.
Proxy climate makes use of proxy climate data also called proxies. These proxies help in inferring about the past climate.
Examples of proxies are;
pollen grainsCoral reefsIce coresTherefore, pollen grains help scientists identify plants and make assumptions on past climate condition.
Learn more about past climate at: https://brainly.com/question/9328022
A hollow glass prism doesnot cause the dispersion of light why?
Please HELP! Its urgent..
Answer:
When white light passes through the prism ,different colours suffers deviation through different angles and light appears to be dispersed. But in a hollow prism dispersion does not take place as all the colours travel with same speed in the air inside hollow prism. Thus no angular dispersion is there.
PSYCHOLOGY
The most widely used psychoactive drug is
ОА.
heroin.
B.
caffeine.
O C.
PCP.
O D.
LSD.
the answer is B.caffeine. Just didn’t see anyone have this question on Brainly yet.
d is the right answer
when a person holds a ball above earth's surface, where is this potential energy stored?
Answer:
in the ball
Explanation:
potential energy is where an object has energy, always, but it isn't always moving, and when you drop the ball, it has kinetic energy.
Only about 50% of the solar energy directed toward Earth penetrates directly to the surface. Explain what happens to the rest of the radiation.
Answer:
it is absorbed or reflected by the atmosphere
Explanation:
In the case when approx 50% only of the solar energy would be directed towards earth and it would be penetrates directly to the surface so the rest or remaining of the radiation would be either absorbed or refected by the atmosphere
So as per the given situation the above represent the answer
hence, the same is to be considered and relevant
When is the world going to end? Give me your opinions and the reasons why you think that.
Answer:
probably when the next pandemic happens
can a plane mirror firm a real image ? if yes tell me how ?
Answer:
Explanation:
A plane mirror will produce a virtual image of a real object. But it is correct that a plane mirror will also produce a real image of a virtual object.A virtual image An image in a mirror is a virtual object, which can in turn be used to create another image. This can occur when you have more than one optical element in the optical system. Then the object of one component becomes the image of the next optical component.
So the answer is Yes it will!!!!
Answer:
I think u know the answer of this question
What element does the picture represent? (Use the periodic table if you need to) *
(1 Point)
nitrogen
O chlorine
O oxygen
help with this pleaseeee i’ll give brainlist:)
Answer:
C. Test to see if your material is strong and works well.
The stone, which weighs 400 g, is thrown upwards at a speed of 20 m / s. Climbed to a height of 12 m. Determine: what is equal to the work of the resistance force; equal to the mean resistance force?
Given that,
Mass of the stone, m = 400 g = 0.4 kg
Initial speed, u = 20 m/s
It is climbed to a height of 12 m.
To find,
The work done by the resistance force.
Solution,
Let v is the final speed. It can be calculated by using the conservation of energy.
[tex]v=\sqrt{2gh} \\\\v=\sqrt{2\times 9.8\times 12} \\\\v=15.33\ m/s[/tex]
Work done is equal to the change in kinetic energy. It can be given as follows :
[tex]W=\dfrac{1}{2}m(v^2-u^2)\\\\=\dfrac{1}{2}\times 0.4\times (15.33^2-20^2)\\\\=-32.99\ J[/tex]
So, the required work done is 32.99 J.
WILL GIVE LOTS OF POINTS!!!!!!
Explain the process of convection in the atmosphere.
Answer : Convection is a major factor in weather. The sun heats the earth's surface, then, when cooler air comes into contact with it, the air warms and rises, creating an upward current in the atmosphere. That current can result in wind, clouds, or other weather.
Explanation:
In the atmosphere convection happens when warm air on the ground rises into the atmosphere(clouds) and at the high altitudes the air becomes cold causing the air to come back down to the surface.
Why is the solar system commonly represented as a scale model?
Please write in complete sentences. I will mark Brainiest to whoever correct.
Select the correct answer.
The goal of the Tariff of Abominations, passed in 1828, was to protect the industries in the
foreign nations. Which statement best shows the effect of this tariff on American history?
ОА.
The Tariff of Abominations widened Income Inequality because it favored the
ОВ.
The Tariff of Abominations upset American Indians because it did nothing pro
OC.
The Tariff of Abominations caused conflicts between the North and the South
OD
The Tariff of Abominations upset common working class Americans because i
Reset
Next
Answer:
OC, The Tariff of Abominations caused conflicts between the North and the South regarding their sectional interests.
Explanation:
The Tariff of Abominations did cause conflicts because it widened income inequality since it favored the rich upper class while burdening the lower class. The South was the lower class, and the North was more of the upper class.
Mass varies depending on where the object is located.
True or false
A 55 kg roller skater is at rest on a flat skating rink, a 198 N horizontal force is needed to set the skater in motion.
However, after the skater is in motion a horizontal force of 175 N is necessary to overcome the friction of 52N to keep
the skater moving at a constant velocity. Find the coefficient of kinetic friction.
Answer:
Explanation:
To get the person Moving you have to overcome the static (means not moving) friction coefficient. U(static)
To get the person going at the same speed you have to overcome the kinetic friction coefficient. U(Kinetic)
Force to get him moving is 198 N. Force = ma = U(static)Mg
combining the 2 equations you get 198N = U(static)* 55kg *9.8m/s^2 Solve for U(static)
Same equation to keep him moving except with the dynamic force and the dynamic U
175N= U(kinetic)*55kg*9.8m/s^2 Solve (U dynamic)
Newton's second law and the expression of the friction force allow to find the result for the value of the kinetic friction coefficient is:
μ = 0.325
Newton's second law establishes a relationship between the net force, mass, and acceleration of the body.
Σ F = m a
Where the bold letters indicate vectors, m is the mass and the acceleration.
The friction force is a macroscopic force that represents the interactions between the two surfaces, it can be of two types:
Static. If there is no relative movement between the two surfaces. Kinetics. If there is relative movement between the two surfaces.The expression in both cases is:
fr = μ N
Where N is the normal and μ is the friction coefficient, one value for the static case and another for the kinetic case.
In the attachment we have a free-body diagram for when the skater is moving with constant speed.
y=axis
N - W = 0
N = W
x-axis
F - fr = 0
F = fr
They indicate that the applied force is F = 175N and the mass of the skater is m = 55 kg.
We substitute.
F = μ mg
μ = [tex]\frac{F}{mg}[/tex]
Let's calculate.
μ =[tex]\frac{175}{55 \ 9.8}[/tex] 175/55 9.8
μ = 0.32
In conclusion, using Newton's second law and the expression of the friction force we can find the result for the value of the coefficient of kinetic friction is:
μ = 0.325
Learn more here: brainly.com/question/1714663
Please help, quicklyyyyy
What units are used to measure mass and weight?
a carbon atom with 6 proton and 6 neutron in its nucleus is called carbon-12 the carbon atom with 8 neutrons is called what
Answer:
carbon-14 must be the answer
An LDR was placed near a light source. The following results were
recorded: potential difference = 5.50V current = 12.5 mA. Which equation
links current, potential difference and resistance? *
Answer:
V = 440I
Explanation:
According to ohm's law which states that the current passing through a metallic conductor at constant temperature is directly proportional to the potential difference across its ends.
Let V be the potential difference
I is the current
R is the resistance
Mathematically;
V∝I
V = IR
Given
Potential difference V = 5.50Volts
Current = 12.5mA = 12.5*10^-3A
Current I = 0.0125A
Recall that V = IR
R = V/I
Substitute the given parameters into the formula;
R = 5.50/0.0125
R = 440 ohms
Hence the equation that links current, potential difference and resistance is expressed as;
V = I(440)
V = 440I
WILL REWARD ASAP Calculate the density of a 25g stone that causes water in a graduated cylinder to
go up by 12.5 ml.
What happens when you call someone using your cell phone?
A. Microwaves travel from your cell phone directly to the cell phone
of the person you are calling.
B. Microwaves reach a cell tower, then fiber optic cables send the
signal to a cell tower near the person you are calling.
C. A system of satellites orbiting Earth receives the microwave
signals and sends them to the person you are calling.
D. Sound waves reach a cell tower, then fiber optic cables send the
signal to a cell tower near the person you are calling.
Answer: B, Microwaves reach a cell tower, then fiber optic cables send the signal to a cell tower near the person you are calling.
Explanation:
Answer:D. Sound waves reach a cell tower, then fiber optic cables send the
signal to a cell tower near the person you are calling.
Explanation: just got it right
HELP I'M LAZY AND D U M B
(please use information from the small text to answer the questions)
1. What do the curved blue lines wrapping around Earth represent?
2. The geomagnetic poles move over time. What causes this to happen?
3. How do Earth's geomagnetic poles differ from its geomagnetic poles?
4. Mars has a week magnetic field. How do you think the conditions on the surface of Mars compare with those on Earth? What would that mean for astronauts traveling to Mars in the future?
Maps can convey a lot of different types of information. They can tell you where you are or they can tell you something about a location. Earth scientists often use maps that have coordinates so that they can locate themselves or the features they are interested in. Different types of maps show different things well. For example, some types of maps show the tropical areas really well but do a terrible job depicting the polar regions.
A 1.0 kg ball is thrown into the air with an initial velocity of 30 m/s. What is the kinetic energy of the ball?
Answer:
If this helps, to work out the kinetic energy the formula is K (stands for kinetic energy) = 1/2 (half of) mass and velocity. So the answer is 450 joules.
Explanation:
Which statement best defines the resistance of an electric circuit? (1 point) o It limits the amount of electrical energy that can pass through a circuit. 0 It is the measurement of the rate of electrical energy in a circuit. O It is the amount of electrical energy that is available in a circuit. O It describes how much electrical energy passes in a circuit.
Answer:
it limits the amount of electrical energy that can pass through a circuit