Answer:
jjjjjjjjjjjjjjjj
Explanation:
Question 3 of 10
What happens to the resistance of a wire as its length decreases?
A. The resistance alternates between high and low values.
B. The resistance increases
ОО
C. The resistance is not affected by a change in wire length.
O D. The resistance decreases.
SUBMIT
B
The resistance of a wire is directly proportional to length of wire. Hence the more the length of wire, the more its resistance.
A compact car can climb a hill in 10 s. The top of the hill is 30 m higher than the
bottom, and the car's mass is 1,000 kg What is the power output of the car?
Answer:
29.4 kW
Explanation:
time t = 10 s, height h = 30 m, mass m = 1,000 kg
power output = work done/time
work done = increase in potential energy = mgh = 1,000 * 9.8 * 30 = 294,000 J = 294 kJ
power output = 294/10 = 29.4 kW
An object started moving with an initial velocity of 10m/s after travelling a distance of 5m gets a velocity of 20m/s find its: (a)acceleration
(b)time taken
Answer: a = 30 m/s^2
t = .33 s
Explanation:
(v final)^2 = (v initial)^2 + 2*a*d → 20^2 = 10^2 + (2)(a)(5) → a = 30 m/s^2
Acceleration = change in velocity / time → 30 = (20 - 10) / t → t = .33 s :)
A lightbulb uses 98 J of electrical energy every second to produce 10 J of light energy in the same time frame. What is the percent efficiency of the lightbulb in converting electricity into light?
Answer:
10.2 % efficiency.
Explanation:
Percent efficiency formula: (output / input) * 100%
The output energy (in Joules) is how much was used eventually. - It is 10 J
The input energy (in Joules) is how much energy was put into the lightbulb initially. It is 98 J
(10 J / 98 J) * 100% = 10.2 % efficiency.
Suppose that a car starts from rest at t = 0. The car moves with an acceleration of 1.5 m/s2. How far will the car travel in 3.0 s?
Answer:
6.75m
Explanation:
To calculate the distance in this question, we can use the formula:
S = ut + 1/2at^2
Where; S = distance
u = initial velocity = 0m/s
t = 3s
a = 1.5m/s^2
Hence:
S = (0 × 3) + 1/2 (1.5 × 3 × 3)
S = 0 + 1/2 (13.5)
S = 13.5/2
S = 6.75
Therefore, the car will travel 6.75m in 3seconds.
To find the distance traveled by the car in 3 seconds is equal to 6.75 meters.
Given the following data:
Initial velocity = 0 m/s (since it starts from rest).Acceleration = 1.5 [tex]m/s^2[/tex]Time = 3 seconds.To find the distance traveled by the car in 3 seconds, we would apply the second equation of motion:
The second equation of motion.Mathematically, the second equation of motion is given by the formula;
[tex]S=ut +\frac{1}{2} at^2[/tex]
Where:
S is the distance traveled.u is the initial velocity.a is the acceleration.t is the time measured in seconds.Substituting the given parameters into the formula, we have;
[tex]S=0(3) +\frac{1}{2} \times 1.5 \times 3^2\\\\S=\frac{1}{2} \times 1.5 \times 9\\\\S = 1.5 \times 4.5[/tex]
Distance, S = 6.75 meters.
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A bus run at 100 km/hr top speed. It can carry a maximum of 6 persons. If speed of bus decreases in fixed proportion with increase in number of person, find speed when three person are traveling in bus.
Answer:
150 km/h
Explanation:
It is given that,
Speed of a bus is 100 km/h and it can carry a maximum of 6 persons.
If speed of bus decreases in fixed proportion with increase in number of person, then we need to find the speed when 3 person are traveling in bus.
6 person = 100 km/h
1 person = (100/6) km/h
Ans
3 person = [tex]\dfrac{100}{6}\times 3=50\ km/h[/tex]
Net speed = 100 km/h + 50 km/h = 150 km/h
Hence, if the required speed is 150 km/h.
According to The first law thermodynamics Energy can be created and destroyed, True or False? 
Answer:
False
Explanation:
energy in terms I've heard at least energy cannot be created or destroyed
As a hiker in Glacier National Park, you are looking for a way to keep the bears from getting at your supply of food. You find a campground that is near an outcropping of ice from one of the glaciers. Part of the ice outcropping forms a slope of angle θup to a vertical cliff. You decide that this is an ideal place to hang your food supply, as the cliff is too tall for a bear to reach it. You put all of your food into a burlap sack, tie an unstretchable rope to the sack, and tie another bag full of rocks to the other end of the rope to act as an anchor. The mass of rocks that you put into the anchor bag is equal to the mass of food in the other bag.What will be the acceleration aof the food bag when you let go of the anchor bag? Assume that the weight of the rope is negligible, and that the ice can be considered frictionless.Express the resulting acceleration aof the food bag in terms of θ and g, the acceleration due to gravity. Let the positive direction for this bag be downwards.
Answer: the acceleration is (g( 1 - sinθ)) / 2
Explanation:
the tension in one bag is expressed as;
T = ma + mg sin θ ........................lets say equ 1
now the tension in another bag is expressed as;
T = -ma + mg..................lets say equ 2
so equate both equations
ma + mg sinθ = -ma + mg
2ma = mg ( 1 - sinθ)
a = (g( 1 - sinθ)) / 2
therefore the acceleration is (g( 1 - sinθ)) / 2
does a radio wave have a high or low frequency
Answer:
Low
Explanation:
Radio waves have photons with the lowest energies.
A boy pulls a wagon with an applied force of 40 N on frictionless surface. If the mass of the wagon is 13kg, what is the acceleration of the wagon?
Answer:
3.1 m/s²
Explanation:
Apply Newton's second law:
∑F = ma
40 N = (13 kg) a
a ≈ 3.1 m/s²
Can someone pls help ! I’m sorry it’s small
Answer:
The velocity time graph which shows a negative constant velocity (horizontal line below the horizontal axis) Labeled as Graph #2
Explanation:
Notice that the position-time graph shows the position decreasing in the form of a line with negative slope. Recall that the velocity graph is associated with the change in position with time, and this change in position is in the form of a line of constant negative slope. The slope of the position-time graph is in fact the velocity of the object, which therefore is negative and constant.
Such behavior is represented by the graph labeled as Graph 2 of a constant (horizontal) line below the horizontal axis.
What does the atomic number of an atom tell us?
Answer:
The atomic number uniquely identifies a chemical element. It is identical to the charge number of the nucleus. In an uncharged atom, the atomic number is also equal to the number of electrons. The sum of the atomic number Z and the number of neutrons N gives the mass number A of an atom.
Explanation:
Answer:
I believe that the atomic number of an atom represents the number of protons in one atom of an element. It also tells you the number of electrons in a neutral atom of that element
Explanation:I hope that this is helpful.
A 100V battery connected to two oppositely charged plates that are 10cm apart.
a. What is the magnitude of the electric field?
b. What is the electric force exerted on a +200uC ?
Answer:
Work to move unit charge from one plate to the other separated by d
W = E q d
Electric potential: V = W / q
E = V / d = 100 Volts / .1 m = 1000 Volts / m
F = E q = 1000 Joule / C m * 2 * 10E-4 C
F = .2 J / m = .2 N
An ideal fluid is moving at 3.0 m/s in a section of a pipe of radius 0.20 m. If the radius in another section is 0.35 m, what is the flow speed there
The flow speed of the fluid in the second section of the pipe is 0.98 m/s
What is flow speed?Flow speed is the rate at which the distance of a fluid changes with respect to time as it moves in a pipe.
To calculate the flow speed in the second section, we use the formula below.
Formula:
AV = A'V'............ Equation 1Where:
A = Cross-sectional area of the first section of the pipeV = Velocity of fluid in the first section of the pipeA' = cross-sectional area in the second section of the pipeV' = Velocity of fluid in the second section of the pipe.Make V' the subject of the equation
V' = AV/A'......... Equation 2From the question,
Given:
A = πR² = 0.04π m²V = 3 m/sA' = πr² = (0.35²×π) = 0.1225π m²Substitute these values into equation 2
V' = 3(0.04π)/(0.1225π)V' = 0.98 m/sHence, The flow speed of the fluid in the second section of the pipe is 0.98 m/s
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-- can some someone please help ----How far did the object move between 0 and 20 s?
m____________
If 2 J of wok is done in raising a 180 g red delicious apple to bring it to your mouth to take a bite of the apple, how far is it lifted?
Answer:
Most likely 2ft
Explanation:
Your arm aint that long
At constant mass, the __________________ of an object varies (directly, inversely) with the net external force applied. That is to say, that an object’s acceleration increases as the force applied is (decreased, increased), but its acceleration decreases if the force applied is (decreased, increased).
At constant force, acceleration varies (directly, inversely) with mass. When subjected to the same amount of net external force, a heavier object will experience (less, greater) acceleration than a lighter one.
An object with a mass of 9 kg weighs 33.3 N on Mars. What is the acceleration due to Mar's gravity?
O 1.6 m/s^2
O 9.8 m/s^2
O 3.7 m/s
O 8.9 m/s
Answer:
3.7m/s^2
Explanation:
Weight (W)= mass (m) x acceleration due to gravity (g)
therefore
g = W/mg
g = 33.3/9
9 = 3.7m/s^2
A container is filled to a depth of 154.7 cm with water. On top of the water floats a 124.5 cm thick layer of oil with specific gravity 0.754. What is the absolute pressure at the bottom of the container
We can talk about the amountofpotential energy per unit chargeas a function of locationâwe use the term voltageto describe this.A voltage difference between two locations results from the presence of an electric field. The more work the field can do in moving thecharge from point A to point B, the higher the voltageof point A is relative to point B.
Required:
a. Describe and draw the electric field between two large, oppositely charged plates.
b. Electric potentialis completely analogous to an object being dropped off of a building. The higher the building, the more potential energy the object has. Make a sketch of the ground and a building anddraw lines that indicate constantpotential energyof an object.
c. On your sketch for part a, draw lines of constant potential (these are called equipotentiallines). It may help to imagine placing a positive charge between the plates. It will accelerate toward the negative plate and run into it. Regardless of where you place the charge on an equipotential line, itâll hit the negative plate with the same speed.
Answer:
potential lines that are perpendicular to the electric field, they must be parallel to the plates
Explanation:
A and C) for this drawing, as the electric field lines go from the positive plate to the negative plate and are horizontal to the potential lines that are perpendicular to the field, they must be parallel to the plates, see attached part a
B) in this case the ground has an energy of zero and the lines are parallel to the ground, see attached part b
A rope is wrapped three and a half times around a cylinder. Determine the range of force T exerted on the free end of the rope for maintaining equilibrium that is required to just support a 5 kN weight. The coefficient of friction between the rope and the cylinder is 0.2
The range of force exerted at the end of the rope is 285.7 N to 1,000 N.
Net horizontal force of the cylinder
The net horizontal force of the cylinder when it is at equilibrium position is determined by applying Newton's second law of motion.
∑F = 0
F - μFn = 0
F - 0.2(5,000) = 0
F - 1,000 = 0
F = 1,000 N
The strength of the applied force increases as the number of turns of the rope increases.
minimum force = total force/number of turns of rope
minimum force = 1,000/3.5
minimum force = 285.7 N
Thus, the range of force exerted at the end of the rope is 285.7 N to 1,000 N.
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1.99 m/s^2 for the first 60.0 m, then decelerates at -0.266 m/s^2 for the final 40.0 m. How much time did the race take?
Time required to complete 60m:-
[tex]\\ \rm\longmapsto s=1/2at^2[/tex]
[tex]\\ \rm\longmapsto 60=1.99/2t^2[/tex]
[tex]\\ \rm\longmapsto 120=1.99t^2[/tex]
[tex]\\ \rm\longmapsto t^2=60.3[/tex]
[tex]\\ \rm\longmapsto t\approx 7.7s[/tex]
Time taken to complete last 40m
[tex]\\ \rm\longmapsto 80=-0.266t^2[/tex]
[tex]\\ \rm\longmapsto t^2=300.75[/tex]
[tex]\\ \rm\longmapsto t\approx 17.3s[/tex]
Total time:-
7.7+17.3=25s(Approx)Answer:
Explanation:
Two kinematics equation
v = u + at
and
s = ut + 1/2(at^2)
where u is initial velocity, v is final velocity, a is acceleration, t is time and s is displacement.
For the first 60m, initial velocity is 0 and acceleration is 1.99.
60 = 0 + 1/2(1.99)t^2
t^2 = 120/1.99
t = 7.765s
Velocity at 60m = 0 + 1.99(7.765) = 15.453 m/s
For the final 40m, initial velocity = 15.453, acceleration is -0.266.
40 = 15.453t' + 1/2(-0.266)t'^2
0.133t'^2 - 15.453t' + 40 = 0
Using the quadratic formula, t' = 2.649s or 113.54s
The solution of 113.54s represents someone running pass the finish line and continuing the deceleration until one runs backwards to the finish line again. So that solution should be rejected.
The total time taken = 7.765 + 2.649
= 10.414s
A ball is thrown upward and let fall down a building. Another identical ball was dropped straight down the building at the same time with the same initial speed as the first ball. How will the velocities of these two balls compare when they each hit the ground? Justify your response.
Answer:
same velocity
Explanation:
energy is conserved-
KE=PE
Calculate the displacement and then velocity for an object 12.77s after it is dropped.
Answer:
799 m
125 m/s
Explanation:
Take down to be positive. Given:
v₀ = 0 m/s
a = 9.8 m/s²
t = 12.77 s
Find: Δy and v
Δy = v₀ t + ½ at²
Δy = (0 m/s) (12.77 s) + ½ (9.8 m/s²) (12.77 s)²
Δy ≈ 799 m
v = at + v₀
v = (9.8 m/s²) (12.77 s) + 0 m/s
v ≈ 125 m/s
Can someone pls help ASAP:(
A 10,000 kg freight car moving at 2 m/s collided with a stationary 30,000 kg freight car. The two cars couple together and move off at what speed?
Answer:
Explanation:
Momentum conservation:
10,000 x 2 = (10,000 + 30,000) x v
so
v = 0.5 m/s
The speed after collision will be = 0.5m/s
What is conservation of momentum ?The conservation of momentum states that the amount of momentum remains constant , momentum is neither be created nor be destroyed but only changes through the actin of forces as described by newton's law of motion
since , momentum should be conserved before and after the collision
so , from momentum conservation we can write ,
m1 = mass of moving freight car = 10000kg
v1 = speed of moving freight car = 2m/s
m2 = mass of stationary freight car = 30000 kg
v2 = speed of stationary freight car = 0 (since , at rest )
M = mass of coupled cars after collision
V = velocity coupled cars after collision
momentum before collision = momentum after collision
m1*v1 + m2*v2 = MV
10000 * (2) + 30,000 * 0 = (10000 + 30000) V
20000 = 40000V
V = 0.5 m/s
The speed after collision will be = 0.5m/s
learn more about conservation of momentum
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Read the following selections from the section "Mickey Guyton's Star-Spangled Banner."
The Grammy Award-nominated country singer delivered a soaring, emotional version of the anthem largely on bet
own. A small choir and piano later joined her.
Guyton did not appear to drop or flub any words. She wore a royal blue gown.
What conclusion is BEST Supported by the selections?
A- Mickey Guyton has performed at some of the previous Super Bowls.
B- Mickey Guyton spent a great deal of time practicing for her performance.
C- Mickey Guyton was nervous about singing the national anthem mostly on her own.
D- Mickey Guyton put her personal touch on an anthem that came off without a hitch.
Answer:
C
Explanation:
Describe Health and Exercise
Answer:
plenty of exercise
Explanation:
If you are unhealthy or not happy with yourself. try this. Do a 30 minute walk everyday and eat normal amounts of food portions a human should have an in a day. Make sure you drink plenty of water. If that doesn't work maybe taking to someone about it and see what information they have for you. These things do work because i was over weight and lost 73 pound just by doing those few things.
What is the average kinetic energy of a molecule of an ideal gas at temperatures of 27°c? what is the total random kinetic energy of the molecule in 1 mole of this gas .what is the RMS of speed of oxygen molecule .
(a) The average kinetic energy of a molecule of an ideal gas is 6.21 x 10⁻²¹ J.
(b) The total random kinetic energy of the molecule in 1 mole of this gas is 3,741.3 J.
(c) The RMS speed of the oxygen molecule is 215.25 m/s.
Average kinetic energy of ideal gasThe average kinetic energy of a molecule of an ideal gas is calculated as follows;
[tex]K .E = \frac{3}{2} K T[/tex]
Where;
K is Boltzmann constant = 1.38066 x 10⁻²³ J/KT is temperature in Kelvin, = 27°c + 273 = 300 K[tex]K.E = \frac{3}{2} \times (1.38 066 \times 10^{-23}) \times 300\\\\K.E = 6.21 \times 10^{-21} \ J[/tex]
Total random kinetic energyThe total random kinetic energy of the molecule in 1 mole of this gas is calculated as follows;
[tex]K.E = \frac{3}{2} nRT\\\\K.E = \frac{3}{2} (1) (8.314)(300)\\\\K.E = 3,741.3 \ J[/tex]
RMS of speed of oxygen moleculeThe RMS speed of the oxygen molecule is calculated as follows;
[tex]K.E = \frac{1}{2} mV_{rms}^2\\\\V_{rms}^2 = \frac{2K.E}{m} \\\\V_{rms} = \sqrt{\frac{2 K.E}{m} }[/tex]
one mole of oxygen gas = 32 g = 0.032 kg
[tex]V_{rms} = \sqrt{\frac{2 \times 741.3 }{0.032} }\\\\V_{rms} = 215.25 \ m/s[/tex]
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If the man has a mass of 90kg, where would he experience greater gravitational force? On Earth or Moon? Calculate and explain
Answer: You feel the gravitation on the Earth greater
Explanation:
Because the mass of the Earth is heavier than the Moon, you can replace specifi number of the weight of the Moon and the man compare the weight of the Earth and the man into the formula!