Answer:
3 to 7 seconds.
Explanation:
According to the traffic engineers the length or the duration of the signal to turn form yellow or amber to green is more than 5 seconds. A time interval is needed to easy out the traffic flow.A bullet with a mass mb=13.5 g is fired into a block of wood at velocity vb=245 m/s. The block is attached to a spring that has a spring constant k of 205 N/m. The block and bullet continue to move, compressing the spring by 35.0 cm before the whole system momentarily comes to a stop. Assuming that the surface on which the block is resting is frictionless, determine the mass mw of the wooden block.
Momentum is conserved, so the sum of the momenta of the bullet and block before collision is equal to the momentum of the combined bullet-block system,
[tex]m_bv_b+m_wv_w = (m_b+m_w)v[/tex]
where v is the speed of the bullet-block system. The block starts at rest so it has no initial momentum, and solving for v gives
[tex]v = \dfrac{m_b}{m_b+m_w} v_b[/tex]
The total work W performed by the spring on the bullet-block system as it is compressed a distance x is
[tex]W = -\dfrac12kx^2[/tex]
where k is the spring constant, and the work done is negative because the restoring force of the spring opposes the bullet-block as it compresses the spring.
By the work-energy theorem, the total work done is equal to the change in the bullet-block's kinetic energy ∆K, so we have
[tex]W_{\rm total} = W = \Delta K[/tex]
The bullet-block starts moving with velocity v found earlier and comes to a stop as the spring slows it down, so we have
[tex]-\dfrac12kx^2 = -\dfrac12(m_b+m_w)v^2 \implies kx^2 = \dfrac{{m_b}^2}{m_b+m_w}{v_b}^2[/tex]
Solve for [tex]m_w[/tex]:
[tex]m_w=\dfrac1k\left(\dfrac{m_bv_b}x\right)^2-m_b[/tex]
[tex]m_w=\dfrac1{205\frac{\rm N}{\rm m}}\left(\dfrac{(0.0135\,\mathrm{kg})\left(245\frac{\rm m}{\rm s}\right)}{0.350\,\rm m}\right)^2-0.0135\,\mathrm{kg}\approx \boxed{0.422\,\mathrm{kg}}[/tex]
Un muelle se alarga 20 cm cuando ejercemos sobre él una fuerza de 24 N. Calcula:El valor de la constante elástica del muelle
Answer:
120 Nm-1
Explanation:
Según la ley de Hooke;
F = Ke
F = fuerza sobre el resorte
K = constante de fuerza
e = extensión
Por eso;
K = F / e
K = 24N / 20 × 10 ^ -2m
K = 120 Nm-1
A converging lens of focal length 20cm, forms a real image twice the size of the object. Calculate:
i) the power of the lens;
ii) the position of the image.
Answer:
Solition given:
focal length(f)=20cm
size of image(v)=2x
size of object(u)=x
we have
power of lens= reciprocal to focal length=1/20=0.05/cm
ii.
the position of the image is beyond C.
Explanation:
See the attachment !!!!!!!
define Neutons 3rd law .
Answer:
that when two object interact, they apply forces to one another that are equal in magnitude and opposite in direction.
Explanation:
Newton's third law: the law of action and reaction
1. How much heat energy ( Q ) is required to heat 2.0 kg of copper from 30.0 oC to 80.0 oC?
Answer:
38500
Explanation:
I looked it up so it may be wrong
the weight of a body is 420 newton.calculate it's mass
Answer:
42g
Explanation:
the mass of a body is given by
m=weight/gravity
=420/10
=42
I hope this helps
What do is mean by environment friendly behaviour?
Why does the weight of a body differ on different celestial bodies of the universe?
Two forces whose resultant is 100N are at right angle to eachother. if one of them makes an angle of 30° with the resultant, determine its magnitude
Let F₁ and F₂ denote the two forces, and R the resultant force.
F₁ and F₂ point perpendicularly to one another, so their dot product is
F₁ • F₂ = 0
We're given that one of these vectors, say F₁, makes an angle with R of 30°, so that
F₁ • R = ||F₁|| ||R|| cos(30°)
But we also have
F₁ • R = F₁ • (F₁ + F₂) = (F₁ • F₁) + (F₁ • F₂) = F₁ • F₁ = ||F₁||²
So, knowing that ||R|| = 100 N, we get that
(100 N) ||F₁|| cos(30°) = ||F₁||²
(100 N) cos(30°) = ||F₁||
||F₁|| ≈ 86.6 N
(And the same would be true for F₂.)
why is it important to have regular super vision of the weights and the measurements in the market?
Answer:
Obeying to weights & measurement regulations in both national and international metrology legislation, standards and test procedures is a requirement to participate in any market because it's aimed to safeguard the consumers and promote fair competition, which provides efficiency and saves unnecessary costs to U.S. businesses and stakeholders.
Explanation:
In the U.S., the National Institute of Standards and Technology (NIST) has an Office of Weights and Measures (OWM) that represents the country in the International Organization of Legal Metrology (OIML)
derive an expression for resistivity of conductor of length l and area of cross section A
Answer
Resistivity R = K * L / A where resistivity is constant for material, L the length of the material and A the area of the material
K = R * A / L where R is the resistance of the material
Ag,Au and Cu are called coinage metals why plzzzz hurry its urgent plzzz
Answer:
This is because these metals are used for minting (making) coins.
Answer:
It is bcz it is used for making coins
Rearrange this equation so it equals d
v=dt
Answer:
Below
Explanation:
To solve for d rearrange the formula v = (d)(t) to:
d = v / t
I'm not to sure if you are using different variables but usually in physics the formula for velocity is v = d / t not v = dt
If you wanted to solve for displacement you would do:
d = (v)(t)
Hope this helps!
The plane of a5cm*8cm rectangular loop of wire is parallel to a 0.19T magnetic field the loop carries a current of 6.2 A. What torque acts on aloop? What is the magnetic moment of the loop?
Answer:
Torque; τ = 4.712 × 10^(-3) J
Magnetic moment; M = 0.0248 J/T
Explanation:
Torque is gotten from the formula;
τ = BIA
Where;
B is magnetic field
I is current
A is area
We are given;
B = 0.19T
I = 6.2A
Rectangle dimensions = 5cm by 8cm = 0.05m by 0.08m
Thus;
Area; A = 0.05m × 0.08m = 0.004 m²
Thus;
τ = 0.19 × 6.2 × 0.004
τ = 4.712 × 10^(-3) J
Formula for the magnetic moment is given by;
M = IA
M = 6.2 × 0.004
M = 0.0248 J/T
20. A semiconductor is a
A) crystalline solid that conducts current under any condition
B) metallic solid that conducts current under any condition
C) metallic solid that conducts current under certain conditions
D) crystalline solid that conducts current under certain conditions
Answer:
D) crystalline solid that conducts current under certain conditions
Explanation:
A semiconductor is any crystalline solid material whose electrical conductivity is intermediary between that of insulators and conductors. That is, a semiconductor does not conduct like a conductor but does more than an insulator.
Based on this, a semiconductor is said to only conduct electricity under certain conditions as opposed to conductors that do so under any condition. Example of semiconductors are silicon, carbon, antimony, arsenic etc.
define 1 second time
Answer:
define 1 second time
One second is the time that elapses during 9,192,631,770 (9.192631770 x 10 9 ) cycles of the radiation produced by the transition between two levels of the cesium 133 atom. ... One second is equal to 1/86,400 of a mean solar day.
Answer:
One part of 86400 part of a day is called one second time.
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Does water exist on Mars? Explain your answer. Why didn't Jupiter become a star during the early.
Answer:
yes water was discovered in mars
Saul is testing an installation and discovers a short circuit what’s causing this
A.high current
B.high voltage
C.low resistance
D.low voltage
Answer:
im pretty sure that it's (A.) High current
Explanation:
pf
not 100% sure, tho
What kind of circuit is the one shown below?
A. Series
B. Parallel
C. Open
D. Combination
That's a parallel circuit. (B)
When current from Point-A reaches the 3-way intersection just to the right of Point-B, it has to make a choice: Either turn left, go through B, and light the lower bulb, or go straight and light the upper bulb.
A circuit that has any "decision" points in it is a parallel circuit. What happens in the real world is: The current splits up. Some of the current that reaches the intersection turns left toward Point-B, and the rest of it goes straight up.
A series circuit is one in which there's only one possible path all the way around. There are no intersections of more than 2 roads, and no electron ever has to decide which way to flow.
An open circuit is one in which there's a break somewhere along the line and electrons can't jump across it. It's like a railroad where a big piece is cut out of the track somewhere. So no trains can travel on that route, and there's no current flowing anywhere in the circuit.
I'm not so sure about a "combination" circuit. I guess you could give that name to a complicated circuit that has some series parts and some parallel-parts. Personally, I'd call that a "series-parallel" circuit. But it really doesn't matter right now. Whatever the word means, the circuit in the picture is definitely not a "combination" circuit.
Answer:
B. Parallel Circuits
Explanation:
A parallel circuit is constructed by connecting the terminals of all the individual load devices so that the same value of voltage appears across each component. In a parallel circuit, charge divides up into separate branches such that there can be more current in one branch than there is in another.
hope i helped
What is not one of the main uses of springs?
A. Bike suspension
B. The seasons
C. Clock making
D. Car suspension
Quick answer
Answer:
b. the seasons
Explanation:
the force between the earth and the body which is at a distance r from the center of the earth is F. What must be this distance for the force to be doubled.
Answer:
Explanation:
The gravitational force between the earth and another body is F = -GM_em/r^2 r where G = 6.67 times 10^-11 Nm^2/kg^2 is the gravitational constant, M_e = 5.97 times 10^24 kg is the mass of the earth, m is the mass of the other body, and r is the position vector of the second body with respect to the centre of the earth.
mercury is commonly used in thermometer give reasons
Answer:
hi
BECAUSE MERCURY IS USED BECAUSE IT is the only liquid available in room temperatureExplanation:
pls mark as a BRAINLIST
List two factors that compression force depends on
The magnitude (size or numerical value) and the direction.
Hope this helps!!! :)
what give negative acceleration ?
Answer:
But negative acceleration means that the rate of change of velocity is negative or velocity decreases. Example: (1) When we apply brakes in a moving car, then negative acceleration acts on it and the car stops. (2) When we throw a ball upwards, then also negative acceleration acts on it.
Explanation:
If it helps you mark me as a brainleast
MATHEMATICALLY A NEGATIVE ACCELERATION MEANS YOU WILL SUBTRACT FROM THE CURRENT VALUE OF THE VELOCITY.
The fluid inside the hydraulic jack has a pressure of 30,000 Pa. If the surface of
the piston that is used to lift an object is 0.1 m’in area, how much weight can
the jack lift?
Explanation:
p = F /A
F = P×A
F = 30,000 Pa / 0.1 m²
F = 300,000 N
Define measurement with 10 points
Answer:
the process of comparing unknown quantities with known standards quantities are known as measurement
define electrical resistance in a metal conductor
Answer:
Resistance is defined as the property of a conductor to resist the flow of charges through it. The resistance of conductor is numerically given as the ratio of potential difference across its length to the current flowing through it.
Explanation:
Answer the following questions 1 What is the difference between mass and weight of an object. Will the mass and weight of an object on the earth be same as their values on Mars ? Why?
Answer:
difference between mass and weight is that mass is amount of matter in a material while weight is a measure of how the force of gravity acts upon that mass.the mass of an object will be same on earth and mars but its weight on both planets will be different.
the slope of a line on a position vs time graph is the
a. velocity
b. time
c. distance
d. displacement
It's the velocity, but only the magnitude. It can't show the direction of the velocity. So it's better to call it speed.
which two phenomena make up electromagnetism?
A) moving charges in an electric current attract each other
B) permanent magnets form a magnetic field from one pole to the other pole
C) an electric current causes a magnetic field around a core of magnetic metal
D) a moving magnet causes an electric current in a magnetic metal
Explanation:
the correct answer is option ( C ) and ( D )
