First term / second mid Exam [1433/ 1434] Q12. A conductor of radius I, length and resistivity p has resistance R. What is the new resistance if it is stretched to 4 times its original length?
Answer:
R' = 4R
Hence, the resistance increases to four times its initial value as well.
Explanation:
The resistance of a conductor in terms of its physical dimensions can be given by the following formula:
[tex]R = \frac{\rho L}{A}\\[/tex] _______ equation (1)
where,
R = Resistance of the conductor
ρ = resistivity of the material of the conductor
L = Length of the conductor
A = Cross-sectional Area of the conductor
Now, if the length of the conductor is increased to four times, keeping other values constant, then:
[tex]R' = \frac{\rho L'}{A}\\\\R' = \frac{\rho (4L)}{A}\\\\R' = 4\frac{\rho L}{A}[/tex]
using equation (1):
R' = 4R
Hence, the resistance increases to four times its initial value as well.
When acceleration and velocity are the in the same direction, the speed will
Answer:
slowing down.
Explanation:
acceleration points in the same direction as the velocity, the object will be speeding up. And if the acceleration points in the opposite direction of the velocity, the object will be slowing down
Which of the following situations best represents a set of balanced forces?
Group of answer choices
A 12 N of force pulling left while a 22 N of force pulls right.
A 6 N of force pulling left while a 10 N of force pulls right.
A 2 N force and a 10 N force pulling left while a 12 N force pulls right.
A 22 N force pulling left while a 6 N force and a 12 N force pulls right.
Answer:
A 2 N force pulling and a 10 N force pulling left while a 12N force pulls right.
If sound waves require a medium (material) to vibrate in order to produce a sound, can sound waves travel in outer space? Why or why not?
Sound waves requires a medium (material) to vibrate in order to produce a sound. So sound waves cannot travel in outer space as it is vacuum.
What is the velocity of a 65 kg runner with 90 kg m/s of momentum.
Answer:
[tex]\boxed {\boxed {\sf v \approx 1.46 \ m/s}}[/tex]
Explanation:
Momentum is the product of mass and velocity.
[tex]p=mv[/tex]
We know the mass is 65 kilograms and the momentum is 90 kilograms meters per second.
[tex]m= 65 \ kg \\p= 95 \ kg \ m/s[/tex]
Substitute the values into the formula.
[tex]95 \ kg \ m/s= 65 \ kg *v[/tex]
Since we are solving for velocity, we must isolate the variable (v). It is being multiplied by 65 kg. The inverse of multiplication is division, so we divide.
[tex]\frac {95 \ kg \ m/s}{65 \ kg }= \frac {65 \ kg *v}{65 \ kg}[/tex]
[tex]\frac {95 \ kg \ m/s}{65 \ kg }=v[/tex]
The kilograms cancel when divided.
[tex]1.46153846 \ m/s=v[/tex]
Let's round to the nearest hundredth. The 1 (in the thousandth place) tells us to leave the 6.
[tex]1.46 \ m/s \approx v[/tex]
The velocity is approximately 1.46 meters per second.
When 525 J of heat is added to 7.6 g of metal at 26°C, the temperature increases to 80°C. What is the specific heat of the metal?
Ans the answer is 0.25J
Explanation
i guess
Which is used to zero a triple beam balance
A.
the pan
B.
a rider
C.
a beam
D.
the tare knob
pls answer this question
Explanation:
on the left side the forces add to 150N
on the right side the forces add to 300
you then take away 150 from 300
=150N to the right
answer Is C
Four round objects of equal mass and radius roll without slipping along a horizontal surface that then bends upward and backward into an arc of half a circle. The objects all have the same linear speed initially. The objects are a hollow cylinder, a solid cylinder, a solid sphere, and a hollow sphere. The objects to go up the arc and exit the are going in the opposite direction they entered without falling off the arc. Now, several trials are run for each object. For each trial, the initial speed of the object is reduced until the object does not make it through the full arc. The speed needed for each object to just make it through the arc is recorded. Which of the following correctly lists the objects in order from fastest to slowest speed needed to make it through the arc?
A. Hollow cylinder, hollow sphere, solid cylinder, solid sphere
B. Hollow cylinder, solid sphere, solid cylinder, hollow sphere
C. Solid sphere, solid cylinder, hollow sphere, hollow cylinder
D. Solid sphere, hollow sphere, solid cylinder, hollow cylinder
E. Hollow sphere, solid cylinder, hollow cylinder, solid sphere
Answer:
A
Explanation:
inertia Equation for All Object is k m R²
inertia Equation of Hollow Cylinder I = m R²
inertia Equation of Solid Cylinder I = ½ m R²
inertia Equation of Hollow Sphere I = ⅔ m R²
inertia Equation of Solid Sphere I = 2/5 m R²
to find the speed needed we can use Mechanical Energy (ME). or Total Energy.
ME = Translation Kinetic Energy + Rotation Kinetic Energi
ME = ½ m v² + ½ I w²
ME = ½ m v² (1 + k)
v² = 2ME / m(1+k)
sinnce all objects have the same mass, we can figure that v² is proportionally with 1/(1+k)
v²(hc) = 1/(1+1) = ½ = 0.5
v = 0.707
v²(sc) = 1/(1+½) = 2/3 = 0.67
v = 0.818
v²(hs) = 1/(1+⅔) = 3/5 = 0.6
v = 0.744
v²(ss) = 1/(1+²/5) = 5/7 = 0.71
v = 0.842
these is the ratio of speed they produce in the end of the arc with initial speed = 0 m/s
so, if we must give speed to the object so that it can reach the end of the arc, the fastest speed is given to hollow cylinder and the slowest speed is given to Solid Sphere
Then the answer is
HC, HS, SC, SS
Solid sphere, solid cylinder, hollow sphere, hollow cylinder correctly lists the objects in order from fastest to slowest speed needed to make it through the arc.
What is inertia?A body's inertia is a characteristic that makes it resist attempts to move it or, if it is already moving, to change the speed or direction of it.
Mathematically:
inertia All Object is = k m R²
inertia of Hollow Cylinder I₁ = m R²
inertia of Solid Cylinder I₂ = ½ m R²
inertia of Hollow Sphere I₃ = ⅔ m R²
inertia of Solid Sphere I₄ = 2/5 m R²
Total kinetic energy of a body while it roll without slipping = Translation Kinetic Energy + Rotation Kinetic Energi
= ½ m v² + ½ I w²
= ½ m v² (1 + k)
= 2 KE / m(1+k)
Since all objects have the same mass and, v² can be expressed as proportionally with 1/(1+k).
For hollow cylinder: v₁² = 1/(1+1) = ½ = 0.5
v₁ = 0.707
For solid cylinder: v₂²= 1/(1+½) = 2/3 = 0.67
v₂ = 0.818
For hollow sphere: v₃² = 1/(1+⅔) = 3/5 = 0.6
v₃ = 0.744
For solid sphere: v₄² = 1/(1+²/5) = 5/7 = 0.71
v ₄= 0.842
The objects in order from fastest to slowest speed needed to make it through the arc are correctly listed as:
solid sphere > solid cylinder > hollow sphere > hollow cylinder.
Option (C) is correct.
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What is the color of lava at its hottest? Help asap
Answer:
the color the lava would be is orange
Explanation:
molten rock, known as magma, erupts through fissures in earths crust becoming lava. If that lava rises above 525 C (977 F) it glows red, with hotter lavas it becomes orange or even yellow.
hope this helps you.
A uniform plank of mass 10kg and length 10m rests on two supports, A and B as shown. A boy of weight 500N stands at a distance of 2m from A. Find the reaction forces U¹ and U² at the supports A and B respectively
Answer:
U² = 142.86 N
U¹ = 357.14 N
Explanation:
Taking summation of the moment about point A, we get the following equilibrium equation: (taking clockwise direction as positive)
[tex]W(2\ m) - U^2(7\ m) = 0[/tex]
where,
W = weight of boy = 500 N
U² = reaction ay B = ?
Therefore,
[tex](500\ N)(2\ m)-(U^2)(7\ m)=0\\U^2=\frac{1000\ Nm}{7\ m}\\[/tex]
U² = 142.86 N
Now, taking summation of forces on the plank. Taking upward direction as positive, for equilibrium position:
[tex]W-U^1-U^2=0\\500\ N - 142.86\ N = U^1\\[/tex]
U¹ = 357.14 N
Seasons are more noticeable in places that are____from to the equator
Farther
Or
Closer
2.gravity and wind move water
True or false
It is for today pls help
Kamal, Kamala, Krishna invert a sum of RS= 30,000 on a business in the ratio 2 : 3 : 5. Find the each of their investment.
Answer:
Explanation:
Kamal, Kamala, Krishna invert in the ratio 2 : 3 : 5.
As 2+3+5 =10, their respective share is 2/10, 3/10 and 5/10.
Sum of investment = 30000Rs
Kamal's investment = 30000 * 2/10 = 6,000 Rs
Kamala's investment = 30000 * 3/10 = 9,000 Rs
Krishna's investment = 30000 * 5/10 = 15,000 Rs
A boy who is riding his bicycle, moves with an initial velocity of 5 m/s. ten second later, he is moving at 15 m/s. what is his acceleration
[tex]\Large {{ \sf {Question :}}} [/tex]
A boy who is riding his bicycle, moves with an initial velocity of 5 m/s. Ten second later, he is moving at 15 m/s. What is his acceleration?[tex]\Large {{ \sf {Given :}}} [/tex]
Initial Velocity (u) - 5 m/sFinal Velocity (v) - 15 m/sTime (t) - 10 sec[tex]\Large {{ \sf {Formulae :}}} [/tex]
If the velocity of an object changes from an initial value u to the final value v in time t, the acceleration a is, [tex]a \: = \frac{v - u}{t} [/tex][tex]\Large {{ \sf {Step-by-step explanation :}}} [/tex][tex]a \: = \frac{v - u}{t} \\ or \: \: a = \frac{(15 - 5)}{10} m \: s^{ - 2} \\ or \: \: a \: = \frac{10}{10}m \: s^{ - 2} \\ or \: \: a = 1m \: s^{ - 2} [/tex]
[tex]\Large {{ \sf {Answer :}}} [/tex]
His acceleration is [tex]1m \: s^{ - 2} [/tex]Which of the following is NOT true about noon in the Northern Hemisphere, on January 1?
A. The sun has reached its highest altitude for that day.
B. Your shadow is the shortest it will be that day.
C. Your shadow points due north.
D. The Sun is directly overhead.
Answer:
The answer is D
Explanation:
Laundry in a clothes dryer often becomes charged with static electricity while drying. Which of these best explains why a clothes dryer often generates static electricity?
A: Heat from the dryer charges the air and produces lightning.
B: Clothes with metal pieces conduct electricity in the dryer.
C: Electrons are transferred as clothes rub against each other in the dryer.
Light travels at the same speed at all times. True False
Answer:
true hope this help :}
Explanation:
How can seismographs be used to predict hurricane intensity?
Answer: The earth is a noisy place. Seismometers, which measure ground movements to detect earthquakes, volcanic eruptions, and manmade explosives, are constantly recording smaller vibrations caused by ocean waves, rushing rivers, and industrial activity.
Explanation:
A student constructs four electric circuits.
Each circuit includes two bulbs and an ammeter.
All the bulbs, all the cells and all the ammeters are identical.
The ammeter readings for the first two circuits are shown.
Use values from the box to complete the ammeter readings for the other two circuits.
Answer:
Part A
The ammeter reading for the current flowing through the second bulb, in the third circuit is 0.43 A
Part B
The ammeter reading for the total current coming from the cell is 0.86 A
Explanation:
The given electric circuit schematics includes;
The number of bulbs in each circuit = 2 bulbs
The number of ammeter in each circuit = 1 ammeter
The number of cells in each circuit = 1
Each circuit have identical bulbs, cells and ammeters
Part A
Ammeter reading for the third circuit
The given reading for the total current going to the cell, [tex]I_T[/tex] = 0.86 A
The reading for the current flowing through one of the bulbs, I₁ = 0.43 A
Therefore, given that the bulbs are arranged in parallel, and the bulbs have identical resistance, 'R', the current flowing in the second bulb, I₂, is given by the current divider rule as follows;
[tex]I_2 = \dfrac{R}{R + R} \times I_T = \dfrac{R}{2 \cdot R} \times I_T = \dfrac{1}{2} \times I_T[/tex]
∴ The ammeter reading for the current flowing through the second bulb, in the third circuit I₂ = (1/2) × (0.86 A) = 0.43 A
Part B
Ammeter reading for the third circuit
The total current coming from the cell = The current passing through the bulbs = I₁ + I₂
The ammeter reading for the total current coming from the cell = 0.43 A + 0.43 A = 0.86 A = [tex]I_T[/tex]
2 What is the net force on an object when you combine a force of 17 N north with a force of 9 N north?
Be sure to include the direction of the force.
Answer:
5N NORTH
Explanation:right on edge
How can I rewrite the equation a - b = d using addition?
Explanation:
A=b+d that is the way to rewrite the equation
Which statement is true of an alpha particle?
A. It is electromagnetic radiation, not a true particle.
B. It is an electron.
C. It is the largest decay particle
D. It is a particle that travels at the speed of light.
Answer:
Atoms are made up of various parts; the nucleus contains minute particles ... neutrons, and the atom's outer shell contains other particles called electrons. ... Physical Forms of Radiation; Radioactive Decay; Nuclear Fission; Ionizing Radiation ... of high-energy waves that can travel great distances at the speed of light and ...
Explanation:
The true statement of an alpha particle is it is an electron. The correct option is B.
What is an alpha particle?The alpha particle are composite particles which consists of two protons and two neutrons tightly bonded together. They are ejected from the inside the nucleus of heavy radioactive particles, also called alpha decay.
Atoms are made up electrons orbiting in outer shells, protons and neutrons in the nucleus. The radioactive particle emit highly ionized radioactive rays which ionize electrons emitting alpha particle.
Thus, the correct option is B.
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If both cars are the same mass and hit each other at the same speed (in opposite directions):
1.) They both come to a stop.
2.) They come out of the collision at random speeds.
3.) They come out of the collision at the same speeds they entered it.
4.) They come out of the collision at the same velocities they entered it.
Only the healthy foods we eat provide
energy to our body
true
false
Answer:
True
Explanation:
Yes absolutely the food which provede us energy is termed as healthy..
Two waves, each with an amplitude of 0.5m are superimposed with constructive interference such that they are in phase. Describe the resultant amplitude
The resultant amplitude of the two waves is 1.0m
Interference occurs when two or more waves are superimposed over each other. These waves can either be destructive or constructive in nature. If the waves are superimposed with constructive interference such that they are in phase, the resultant amplitude will be the sum of the amplitude of both waves.Resultant amplitude = 0.5m + 0.5m
Resultant amplutude = 1.0m
Hence the resultant amplitude of the two waves is 1.0m
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Which of the following best describes the circuit shown below?
A. Short
B. Combination
C. Series
D. Parallel
Answer:
The answer is C. Series.
A small person was running way faster than a bigger person that weighed more collided in a football game. Who would be pushed back or down?
Answer:
smaller one
Explanation:
even though he is moving quicker doesn't mean he will be packing more force in the collision
Is sodium chloride a reactant
Answer:
yes it is a reactant
how is momentum of an object related to stopping distance
Answer:
To stop a car must lose its momentum and its kinetic energy. ... If the forces on two cars are equal then the greater the kinetic energy the greater the distance before stopping. But there will be a relationship to the momentum because momentum and mass are both related to the kinetic energy.
A decibel measures the _____________ of sound.
A.pitch
B,frequency
C.loudness
D.amplitude