Answer:
B
Explanation:
the Halogen families have 7 valence electrons
is there any machine that is 100% efficient? why?why not
Answer:
No, it's not there.
Explanation:
For a machine to be 100% efficient, it has to be with an output which is equal to its input. But machines have an out put less than an input, hence efficiency below 100%.
Which of the following is true of highly conductive elements?
Answer:
A
Explanation:
i think a is the answer because if you take an example of group 1 and 2 metals on the periodic table you will notice that they are highly reactive but they have a few electrons in their outer most shells.
I hope this helps
help me with this one
Answer:
may be d)45°
Explanation:
A block of amber is placed in water and a laser beam travels from the water through the amber. The angle of incidence is 35 degrees while the angle of refraction is 24 degrees. What is the index of refraction of amber?
(index of refraction of water is 1.33)
Please help!! :)
For this circuit, what will be the voltage drop across R1?
A. 21.3 V
B. 14.2 V
C. 45.0 V
D. 9.47 V
Answer:
Option D. 9.47 V
Explanation:
We'll begin by calculating the equivalent resistance of the circuit. This can be obtained as follow:
Resistor 1 (R₁) = 20 Ω
Resistor 2 (R₂) = 30 Ω
Resistor 3 (R₃) = 45 Ω
Equivalent Resistance (R) =?
R = R₁ + R₂ + R₃ (series connections)
R = 20 + 30 + 45
R = 95 Ω
Next, we shall determine the current in the circuit. This can be obtained as follow:
Voltage (V) = 45 V
Equivalent Resistance (R) = 95 Ω
Current (I) =?
V = IR
45 = I × 95
Divide both side by 95
I = 45 / 95
I = 0.4737 A
Finally, we shall determine, the voltage across R₁. This can be obtained as follow:
NOTE: Since the resistors are in series connection, the same current will pass through them.
Current (I) = 0.4737 A
Resistor 1 (R₁) = 20 Ω
Voltage 1 (V₁) =?
V₁ = IR₁
V₁ = 0.4737 × 20
V₁ = 9.47 V
Therefore, the voltage across R₁ is 9.47 V.
Answer:
9.47
Explanation:
Just Took the Test
A magnet falls through a loop of wire with the south pole entering first. After it has fallen all the way through the wire loop so that the north pole end is moving away from the loop, what is the direction of the induced current in the loop (as viewed from above, looking down on the magnet)
Answer:
The induced current direction as viewed is clockwise
Explanation:
Lenz's Law states that the induced e. m. f. causes current to be driven in the loop of wire in such a way as to generate magnetic field that are oppose the magnetic flux change which is the source of the induced current
Therefore, as the magnet approaches the coil with the south pole, the coil produces current equivalent to the upward movement of the south pole of a permanent magnet through it which according to Flemings Right Hand Rule is clockwise
Therefore;
The direction of the induced current in the loop (as viewed from above, looking down the magnet) is clockwise
The unit of work in terms of Newton and metre is _______
Answer:
Joule
Explanation:
the unit of work is Joule determined by the letter J.
Answer:
JouleExplanation:
Joule is defined as the work done by a force of one newton causing a displacement of one meter. Sometimes, newton-metre (N-m) is also used for measuring work.
When n resistance each of value x are connected parallel then resultant resistance x. When these n resistor connected in series. Total resistance
Answer:
Explanation:
Suppose you have 3 resistors each with a value of 3. If you placed them in parallel, would you get 3
1/3 + 1/3 + 1/3 = 1/r
The denominator doesn't change. So add the numerators.
(1 + 1 + 1)/3 = 3/3 = 1
So the question is faulty.
1 = 1/r
1*r = 1
r = 1/1
r = 1
Con lắc lò xo có độ cứng k = 100N/m được gắn vật có khối lượng m=0.1kg, kéo vật ra khỏi vị trí cân bằng 1 đoạn 5cm rồi buông tay cho vật dao động. Tính vmax vật có thể đạt được
Answer:
The maximum velocity is 1.58 m/s.
Explanation:
A spring pendulum with stiffness k = 100N/m is attached to an object of mass m = 0.1kg, pulls the object out of the equilibrium position by a distance of 5cm, and then lets go of the hand for the oscillating object. Calculate the achievable vmax.
Spring constant, K = 100 N/m
mass, m = 0.1 kg
Amplitude, A = 5 cm = 0.05 m
Let the angular frequency is w.
[tex]w = \sqrt{K}{m}\\\\w = \sqrt{100}{0.1}\\\\w = 31.6 rad/s[/tex]
The maximum velocity is
[tex]v_{max} = w A\\\\v_{max} = 31.6\times 0.05 = 1.58 m/s[/tex]
A ball that has a mechanical energy of 65 J has 12 J of kinetic energy. The ball has
J of potential energy
Answer:
The ball has a potential energy of 53 J.
Explanation:
Mechanical energy, E = Kinetic energy + Potential energy
E = K.E + P.E
65 = 12 + P.E
P.E = 65 – 12
P.E = 53 J
Therefore the potential energy of the ball is 53 J
Answer:
53
Explanation:
on e2021
People who get population education are also aware of health issues and environment education justify
is noise energy a kind of energy or not
Which type of wires (copper, aluminum, or string) are ferromagnetic metals?
Answer:
Copper isn't ferromagnetic,
Aluminum isn't ferromagnetic,
String has a ferromagnetic property
So in conclusion:
The answer is strings :)
For problems 2-3, a Ferrari accelerates from 0-60.0 miles per hour in 2.50 seconds.
2. What is its final speed, in m/s?
a 5.6 m/s
b. 13 m/s
c. 26.8 m/s
d. 1608 m/s
0-60.0 per near
2.50 seconds
3. What is its average acceleration?
a. 24.0 m/s
b. 10.7 m/s2
c. 38.6 m/s2
d. 13 m/s
Answer:
Explanation:
The first part of this question is simply asking us to convert the speed from miles per hour to meters per second:
[tex]60.0\frac{mi}{hr}*\frac{1hr}{3600sec}*\frac{1609.34m}{1mi}=26.8\frac{m}{s}[/tex] choice C.
The next part wants us to use the equation for acceleration and find the acceleration:
[tex]a=\frac{v-v_0}{t}[/tex] where v is final velocity, v0 is initial velocity, and t is time in seconds (which was one of the reasons we had to convert the initial velocity from 60.0 mph to m/s):
[tex]a=\frac{26.8-0}{2.5}[/tex] and
a = 10.7 m/s/s, choice B.
If the ring rolls (without slipping) all the way to point 2, what is the ring's energy at point 2 in terms of h2 and v2?
Answer:
Following are the response to the given question:
Explanation:
[tex]F_2=mgh_2+\frac{1}{2}mv_2^2+\frac{1}{2}mR^2(W)^2\\\\\therefore \\\\ \to WR=v_2\\\\E_2=Mgh_2+MV_2^2[/tex]
Two boys X and Y each have the same total weight
and are standing on soft ground.
Which boy is more likely to sink into the soft ground and
why?
boy more
likely to sink
pressure on soft
ground
А
Х
larger than Y
B
Х
smaller than Y
C
Y
larger than X
D
Y
smaller than X
Answer:
the child with the smallest area will be the one who sinks
Explanation:
The child who will sink to the ground is the one who exerts the greatest pressure on the ground, even though the force, which in this case is equal to the weight, is equal.
Pressure is defined by
P = F / A
in this case the strength of the children is their weight
F = W
P = W / A
therefore the pressure changes are in the area of contact with the ground, the child with the smallest area will be the one who sinks
if a person buys 10 kg apples in himalayan region and sells in terai region will he get profit or loss. why?
Answer:
he will be in profit
Explanation:
Himalayan region are high above the sea level so the gravity will be less there compared to the Terai region
Terai lies way below he Himalayan region so the pull of gravity will be more compared to Himalayan region
that's why he will be in profit but not loss
If there is 3.4 m3 of methane gas in a container with a pressure of 18.9 atm and the container expands until the methane has a pressure of 2.2 atm, what is the final volume of the methane? Temperature is constant at 305 K. A. 12.23 m3 B. 141.37 m3 C. 29.21 m3 OD. 2.53 m3
Answer:
C. 29.21 m³
Explanation:
Given the following data;
Initial volume, V1 = 3.4 m³Initial pressure, P1 = 18.9 atmFinal pressure, P2 = 2.2 atmTo find the final volume, we would use Boyle's law;
Boyles states that when the temperature of an ideal gas is kept constant, the pressure of the gas is inversely proportional to the volume occupied by the gas.
Mathematically, Boyles law is given by;
PV = K
[tex] P_{1}V_{1} = P_{2}V_{2} [/tex]
Making V2 the subject of formula, we have;
[tex] V_{2} = \frac {P_{1}V_{1}}{P_{2}} [/tex]
Substituting the values into the formula, we have;
[tex] V_{2} = \frac {18.9 * 3.4}{2.2} [/tex]
[tex] V_{2} = \frac {64.26}{2.2} [/tex]
Final volume, V2 = 29.21 m³
A force of 15N acts on an area of 60m².What is the pressure? *
Answer:
0.25p.a
Explanation:
force=15N area=60m²
so pressure =force/area =15N/60m²=0.25p.a
An object is thrown from the ground with an initial velocity of 30 m/s. What is the velocity at the point 25 m above the ground?
Answer:
It's a pretty simple suvat linear projectile motion question, using the following equation and plugging in your values it's a pretty trivial calculation.
V^2=U^2+2*a*x
V=0 (as it is at max height)
U=30ms^-1 (initial speed)
a=-g /-9.8ms^-2 (as it is moving against gravity)
x is the variable you want to calculate (height)
0=30^2+2*(-9.8)*x
x=-30^2/2*-9.8
x=45.92m
Answer:
35
Explanation:
dfddffffffffffffdddfr
A flat, circular, copper loop of radius r is at rest in a uniform magnetic field of magnitude B that extends far beyond the edge of the loop. The plane of the loop is parallel to the page and the magnetic field is directed perpendicular to and out of the page, as indicated by the blue dots. If the magnitude of the magnetic field is decreased at a rate of 1 T/s, what is true about the induced current in the copper loop
Answer:
i =[tex]- \frac{r \ A'}{2 \ rho}[/tex] , i = 0.92 A
Explanation:
This exercise asks for the electromotive force, which can be calculated with Faraday's law
fem = [tex]- \frac{d \Phi_B }{dt}[/tex]
where the magnetic flux
Ф = B. A
bold letters indicate vectors. We can write this equation
Ф = B A cos θ
In this case the magnetic field is perpendicular to the page and the normal to the loop of the loop is also parallel to the page, therefore the angle is zero and the cosine is 1
the loop is
A = π r²
we substitute in the first equation
fem = - π r² [tex]\frac{dB}{dt}[/tex]
we substitute the values
fem = -π r² 1
fem = - π r²
to calculate the current let's use ohm's law
V = i R
R = ρ L / A'
where A 'is the area of the wire and L is the length of the loop
L = 2π r
V = i (ρ 2π r / A ')
I = [tex]\frac{V \ A'}{2\pi \ r \ rho}[/tex]
In this case
V = fem
I = fem / R
i =[tex]- \frac{r \ A'}{2 \ rho}[/tex]
In order to complete the calculation, you need the radius of the loop and / or the wire cutter.
if we assume that the loop has a radius of r = 1 cm = 0.01 m and an area of the wire A'= π 10⁻⁶ m² a radius of the wire 1 mm
i = - 10⁻² π 10⁻⁶ / ( 2 1.7 10-8)
i = 0.92 A
Quả bóng 200g chuyển động với v 4m/s đập vào tường rồi bật ra ngược chiều với cùng tốc độ độ biến thiên động lượng của quả bóng là
(b) The power rating of an electrical appliance at 750watt,calculate consumed for using the appliance for 1 hour.
Answer:
750 w : time = 1hour
Explanation:
750x1hour
=750 watt-hours
what ia measurement in science?
= The process of comparing an unknown quantities with an standard known quantities is called measurement.
Yes it is the measurement in science
A ball is thrown vertically upward.It's velocity at the highest point is?
A. 10 ms^-1
B. Zero
C. 10 ms^-2
D. None of these
B
Explanation:
BECAUSE IT WAS GOING UPWORD THEN IT'S VELOCITY WAS DECREASING -10MS¹
Answer:
Explanation:
From physics, which is directly related to math (especially when it comes to parabolic motion!), we learn that at the very top of the parabola the object has to stop for a millisecond so it can turn around and fall back to earth. This translates to a velocity of 0 at its highest point. So B.
HELP ASAP!!!
What size object (impactor) may create such a crater?
Answer:
I HOPE IT WILL HELP YOU.
:D
The electrical resistance of an element in a platinum resistance thermometer at 100°c, 0°c and room temperature are 75.00Ω, 63.00Ω and 64.992Ω respectively. Use the data to calculate room temperature
Answer:
16.6 °C
Explanation:
From the question given above, the following data were obtained:
Temperature at upper fixed point (Tᵤ) = 100 °C
Resistance at upper fixed point (Rᵤ) = 75 Ω
Temperature at lower fixed point (Tₗ) = 0 °C
Resistance at lower fixed point (Rₗ) = 63.00Ω
Resistance at room temperature (R) = 64.992 Ω
Room temperature (T) =?
T – Tₗ / Tᵤ – Tₗ = R – Rₗ / Rᵤ – Rₗ
T – 0 / 100 – 0 = 64.992 – 63 / 75 – 63
T / 100 = 1.992 / 12
Cross multiply
T × 12 = 100 × 1.992
T × 12 = 199.2
Divide both side by 12
T = 199.2 / 12
T = 16.6 °C
Thus, the room temperature is 16.6 °C
I NEED HELP ASAP!!!
What is the average speed shown on the graph between point A and point D?
Answer:
5/3 m/s or
6 km/h
Explanation:
really ? the average speed is just the straight connection in the graph from A to D.
that means the travel time was 40-10 seconds = 30 seconds.
and the distance traveled was 60-10 = 50 meters.
so, the average speed was
50 meters / 30 seconds
to bring this to standard m/s
5 m / 3 s = 5/3 m/s
or to standard km/h
an hour has 60 minutes or 120 30-seconds intervals
50 m/ 30 s × 120/120 = 6000 m / h = 6 km/h
A long distance runner running a 5km track is pacing himself by running 4.5km/h at 9km/h and the rest at 12.5km/h9
Complete Question:
A long distance runner running a 5.0km track is pacing himself by running 4.5km at 9.0km/hr and the rest at 12.5km/hr. What is the average speed?
Answer:
Average speed = 9.7333 km/h
Explanation:
Let the total distance be divided into A and B.Given the following data;
Total distance = 5 kmDistance A = 4.5 kmSpeed A = 9.5 km/hrSpeed B = 12.5 km/hrTo find the average speed;
First of all, we would determine the time taken to cover distance A in speed A by using the formula;
[tex] Time \ A = \frac {Distance \; A}{Speed \; A} [/tex]
Substituting the values into the formula, we have;
[tex] Time \ A = \frac {4.5}{9.5} [/tex]
Time A = 0.4737 hours
Total distance = distance A + distance B
5 = 4.5 + distance B
Distance B = 5 - 4.5
Distance B = 0.5 Km
Next, we would determine the time to cover distance B in speed B;
[tex] Time \ B = \frac {0.5}{12.5} [/tex]
Time A = 0.04 hours
Total time = time A + time B
Total time = 0.4737 + 0.04
Total time = 0.5137 hours
Now, we would solve for the average speed;
Mathematically, the average speed of an object is given by the formula;
[tex] Average \; speed = \frac {total \; distance}{total \; time} [/tex]
[tex] Average \; speed = \frac {5}{0.5137} [/tex]
Average speed = 9.7333 km/h
What is the electric potential of a 4.5x10^-5 C charge that has an electric potential energy of 0.027 J?
Answer:
600 volts
Explanation: just do 4.5x10^-5c lol i hope this helps if it dont im so sorry
