Answer:
I'm leaning twards A
Explanation:
A speed skater moving across frictionless ice at 8.8 m/s hits a 6.0 m -wide patch of rough ice. She slows steadily, then continues on at 5.8 m/s . What is her acceleration on the rough ice?
Recall that
v² - u² = 2 a ∆x
where u and v are initial and final velocities, respectively; a is acceleration; and ∆x is the distance traveled (because the skater moves in only one direction).
So we have
(5.8 m/s)² - (8.8 m/s)² = 2 a (6.0 m)
a = ((5.8 m/s)² - (8.8 m/s)²) / (12 m)
a = -3.65 m/s²
A power cycle operating between hot and cold reservoirs at 500 K and 300 K, respectively, receives 1000 kJ by heat transfer from the hot reservoir. The magnitude of the energy discharged by heat transfer to the cold reservoir must satisfy
Answer:
The value is [tex]Q_l \ge 600\ k J[/tex]
Explanation:
From the question we are told that
The temperature of hot is [tex]T_h = 500 \ K[/tex]
The temperature of cold is [tex]T_c = 300 \ K[/tex]
The energy received is [tex]E = 1000 \ kJ = 1000 *10^{3 } \ J[/tex]
Generally the maximum thermal efficiency of the engine is mathematically represented as
[tex]\eta = \frac{T_h - T_c}{T_h}[/tex]
=> [tex]\eta = \frac{500 - 300}{500}[/tex]
=> [tex]\eta = 0.4[/tex]
Generally the thermal efficiency of the engine is
[tex]\eta_t = \frac{Q - Q_l}{Q}[/tex]
Here [tex]Q_l[/tex] is the heat energy rejected
Generally the thermal efficiency must be less than or equal to the maximum thermal efficiency
So
[tex]\frac{Q - Q_l}{Q} \le 0.4[/tex]
=> [tex]\frac{1000 *10^{3} - Q_l}{1000 *10^{3} } \le 0.4[/tex]
the change in inequality sign is because [tex]1000*10^{3}[/tex] which was dividing started multiplying
=> [tex]Q_l \ge 1000*10^{3} - 400*10^{-3}[/tex]
=> [tex]Q_l \ge 600*10^{3} \ J[/tex]
=> [tex]Q_l \ge 600\ k J[/tex]
What is velocity in science
Answer:
Velocity is the rate at which the position changes. The average velocity is the displacement or position change (a vector quantity) per time ratio.
Hope this helps! ^-^
Answer:
Velocity is the speed at which something moves in one direction.
Explanation:
Hope this helps : )!!
Write the vectors labeled A, B and C with rectangular coordinates.
Focus on vector A. Start at the base of the vector which is at (1,1)
Then notice how we have to move 3 units to the right and 2 units up to get to the tip of the vector where the arrow is located. So this is at (4,3)
The fact that we moved 3 units to the right and 2 units up means that vector A is <3, 2>
So we'll type 3 in the first box and 2 in the second box.
======================================================
We use the same idea for vector B
Start at the base and move to the tip. Doing so has us move 1 unit left and 3 units down.
Vector B = <-1, -3>
We type -1 in the first box, and -3 in the second box.
======================================================
Finally onto vector C
Start at the base (0,0). To move to the tip, we need to go 3 units left and 3 units up
Vector C = <-3, 3>
-3 goes in the first box and 3 goes in the second box
======================================================
In general, vectors are useful to tell us a specific direction in which to go. They're useful in physics to determine how exactly a force is being applied, or how a particle is moving.
4. A 65 kg woman is inside an elevator. Calculate her apparent weight (Normal Force) for the following cases:
a. The elevator moves at constant speed of 10 m/s downward (2 pts)
b. The elevator accelerates upward at a constant rate of 2.4 m/s2 (2 pts)
c. If the scale read 450 N. Find the magnitude and direction of the elevator’s acceleration. (3 pts)
Answer:
Explanation:
a ) Let her apparent weight be W₁
Net force on her = W₁ - mg
acceleration a = 0
W₁ - mg = 0
W₁ = mg = 65 x 9.8 = 637 N
b )
a = 2.4 m /s²
W₁ - mg = ma
W₁ = m(g + a )
= 65 x ( 9.8 + 2.4 )
= 793 N
c )
W₁ = 450 N
a = ?
W₁ - mg = ma
450 - 65 x 9.8 = 65 x a
65 a = - 187
a = - 2.87 m /s²
acceleration is negative therefore , it must be downwards .
The elevator was accelerating downward at a constant rate of -3.1 m/s²
Let the acceleration due to gravity (g) = 10 m/s²
a) When moving at constant speed of 10 m/s downward:
Net force = mass * g = 65 kg * 10 m/s² = 650N
b) Net force = Mass * g + mass * acceleration
Net force = (65 * 10) + (65 * 2.4) = 806 N
c) Net force = Mass * g + mass * acceleration
450 = 65 * 10 + (65*a)
65a = -200
a = -3.1 m/s²
The elevator was accelerating downward at a constant rate of -3.1 m/s²
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What statements accurately describe sunspots? Check all that apply.
Sunspots are storms on the Sun's surface.
Sunspots are marked by intense magnetic activity.
Sunspots produce solar flares and hot gassy ejections.
Sunspots can affect Earth's climate.
Sunspots are cool areas where the Sun is covered by clouds.
Answer:
sunspots are storms on the Suns surface
Sunspots are marked by intense magnetic activity
Sunspots produce solar flares and hot gassy ejections.
Sunspots can affect Earth’s climate.
Explanation:
I just did this lesson
The statement that describe sunspot is Sunspots are storms on the Sun's surface.
What are sunspot?Sunspot are region of the earth that are more darker than other surfaces. They have temporary spots that are darker because the temperature of that area is cooler than other surfaces. They have a reduced temperature.
Therefore, The statement that describe sunspot is Sunspots are storms on the Sun's surface.
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Explain how the ESPN network has helped the sports industry grow in the past thirty years. In your explanation, you must also explain whether the industry has peaked or whether potential for growth still exists.
Answer:
Thirty years ago, the culture of American sports took a new course. An idea shouldered by a former sports communication executive, along with his son and other partners, would go on to transform the way we consume, analyze and interpret the world of athletics, and would influence international sport culture as well. While sports have always acted as a medium for those looking to escape the drudgeries of work, a way to channel negative emotions into something engaging and entertaining, ESPN presented a new opportunity for fans: an all-encompassing cable network for not only sports itself but also for the culture surrounding sports.,
Explanation:
Hope this helped!
Suppose a rocket-propelled motorcycle is fi red from rest horizontally across a canyon 1.00 km wide. (a) What minimum constant acceleration in the x-direction must be provided by the engines so the cycle crosses safely if the opposite side is 0.750 km lower than the starting point? (b) At what speed does the motorcycle land if it maintains this constant horizontal component of acceleration? Neglect air drag, but remember that gravity is still acting in the negative y-direction.
Which statement describes S waves? A. They move side to side.B.They arrive betore P waves. C. They travel through liquids D. They occur at Earth's surtace.
Answer: they move side to side
Explanation:
i took the test
answer
prove that p = d g h
Answer:
Proving LHS=RHS
Explanation:
Given
p=dgh
Multiplying by 0 on both sides of the equations
p×0=dgh×0
0=0
:- Hence proved
1.What is the mass of an object that weighs 98 N?
Answer:
10 kg
Explanation:
Two wires A and B made of the same material and having the same lengths are connected across the same voltage source. If the power supplied to wire A is six times the power supplied to wire B, what is the ratio of their diameters
Answer:
sqrt (3) : sqrt (2)
Explanation:
Given that Two wires A and B made of the same material and having the same lengths are connected across the same voltage source.
Since they are both made of the same material, they will have the same resistivity.
Resistance is directly proportional to the length of the wire and inversely proportional to the cross sectional area.
Resistance R =1/ πr^2
If the power supplied to wire A is six times the power supplied to wire B, that is,
Pa = 6Pb
Where
Power P = IV
Since the same voltage passes through both wires,
P = V^2/R
Substitutes resistance R into the equation .Therefore,
V^2 ÷ 1 / πr^2 = 6( V^2 ÷ 1 / πr^2 )
V will cancel out , leaving
πr^2 = 6πr^2
Pi( π) will also cancel out. And since diameter d = 2r
r = d/2
Substitutes r into the equation
(d/2)^2 = 6( d/2)^2
d^2/4 = 6( d^2/4)
d^2/4 = 3d^2/2
da^2/2 = 3db^2
(Da/Db)^2 = 3/2
Da : Db = sqrt (3) : sqrt (2)
therefore, the ratio of their diameters is
sqrt (3) : sqrt (2)
The ratio of the diameter of Wire A to Wire B is; √6 : 1
What is the power in the wire?Since both wires are made of the same material, they will definitely have the same resistivity.
Formula for the resistance with area is;
R = 1/A = 1/(πr²)
We are told that the power supplied to wire A is six times the power supplied to wire B. Thus;,
Pa = 6Pb
Since the same voltage passes through both wires, then formula for power in both cases is; P = V²/R. Thus;
V² ÷ (1/πr_a²) = 6(V² ÷ (1/πr_b²))
V and π will cancel out to give;
r_a² = 6r_b²
We know that radius; r = d/2
Thus;
(d_a/2)²= 6(d_b/2)²
d_a²/4 = 6(d_b²/4)
(d_a/d_b)² = 6
d_a/d_b = √6 : 1
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Which landform represents a piece of land that is formed when a river splits before flowing into the ocean?
Delta
Glacier
Lake
Mountain
Answer:
delta
Explanation:i just got it right
A 2070 kg space station orbits Earth at an altitude of 5.37×105 m. Find the magnitude of the force with which the space station attracts Earth. The ma
Answer:
9.9 × 10^-16N
Explanation:
Given that a 2070 kg space station orbits Earth at an altitude of 5.37×105 m. Find the magnitude of the force with which the space station attracts Earth.
Calculating the gravitational field strength.
g = Gm/R^2
Where G = 6.67408 × 10-11 m3 kg-1 s-2
g =(6.67408 × 10-11 × 2070)/5.37 × 10^5
g = 1.38069×10^-7 / 2.88369^11
g = 4.788×10^-19 m/s
Force F = mg
Substitute g into the formula
F = 2070 × 4.79×10^-19
F = 9.9 × 10^-16N
Which of the following is an example of homeostasis?
Answer:
Humans' internal body temperature is a great example of homeostasis. ...
Glucose is the most basic form of sugar, and the only type the body can use directly. ...
When bacteria or viruses that can make you ill get into your body, your lymphatic system kicks in to help maintain homeostasis.
Explanation:
Your car is initially at rest when your hit that gas and the car begins to accelerate at a rate of 2.857 m/s/s. The acceleration lasts for 15.5 s. What is the final speed of the car and how much ground does it cover during this acceleration?
Answer:
Vf = 44.56 [m/s]
Explanation:
In order to solve this problem we must use the following expression of kinematics.
[tex]v_{f} = v_{i}+(a*t)[/tex]
where:
Vf = final velocity [m/s]
Vi = initial velocity = 0
a = acceleration = 2.857 [m/s^2]
t = time = 15.5 [s]
Note: the initial velocity is equal to zero as the car begins its movement from rest, or with an initial velocity equal to zero.
Vf = 0 + (2.875*15.5)
Vf = 44.56 [m/s]
I am so close to wanting to drop out of physics
I'm in college and idk why physics has to be this tough. I took physics back in high school, and it was super easy & I had a really nice teacher.
But now that I'm in college, my professor does no help and literally 60 people dropped out of his class bc his class is hard. I am going to fail my midterm this week. idk what to do and Im sick and tired but its a requirement.
I literally wanna drop out of college bc of physics
Answer: Dont drop out i know school can be a headache but if you try you can accomplished anything.
Explanation:
Answer:
college vs high school.
Explanation:
hello! first, i see the comparison between college and highschool. remember that college professors are much more strict. they dont give participation awards or guide you. this is the time to push yourself! your so close to your goal, why give up from one class? you got this! every question you get wrong or right is a step closer to understanding it better. dont give up. i hope i could help!
What President is responsible for eliminating most vending machines from the cafeterias of public schools ?
Answer:president obama
Explanation:Why this is because he took a of mayor Bloomebergs amti obeity book and made new rules for snack foods.
PLZ HELP!!!!!!! ILL GIVE U BRAINLIEST
Answer:
Claim: Heart Rate for Sarah and Matt (this would be the homeostasis AT REST and throughout the graph time)
Evidence: The Graph and the HR/S and its evidence towards the heart rate/beats every 15 seconds, due to the homeostasis being a specific time limit and due to the specific heart rate of Matt and Sarah ONLY.
Explanation: A/B Checkpoint throughout the homeostasis (this would be heart rate/trial throughout the time of the graph)
Conclusion: Matt was further away ONLY BECAUSE Sarah has a higher Heart Rate during the time on the graph, which can represent how long they did something to increase/decrease from and where the homeostasis would be located.
Answer:
Claim: Heart Rate for Sarah and Matt (this would be the homeostasis AT REST and throughout the graph time)
Evidence: The Graph and the HR/S and its evidence towards the heart rate/beats every 15 seconds, due to the homeostasis being a specific time limit and due to the specific heart rate of Matt and Sarah ONLY.
Explanation: A/B Checkpoint throughout the homeostasis (this would be heart rate/trial throughout the time of the graph)
Conclusion: Matt was further away ONLY BECAUSE Sarah has a higher Heart Rate during the time on the graph, which can represent how long they did something to increase/decrease from and where the homeostasis would be located.
Hellllllpppppp what happens
Answer:
u can write ur answer and submit it
its a test
A yo-yo is attached to the end of a string. A professional yo yo is spinning it by the string around in a circular
motion. All of a sudden he lets go of the string. What direction is the yo yo moving in initially?
Answer:
counter-clockwise
Explanation:
The cheetah, the fastest land animal, can sprint at 30 m/s. Could the cheetah get a speeding
ticket on a highway where the speed limit is 55 mph?
Answer:
#1, cheetas can't go 30 miles per second. #2 no
Explanation:
No because animals can't get tickets.
Answer:
yes
Explanation:
it would be going 67.108 mph,
Sand is made of tiny pieces of rock that have been worn
down by wind and water. Explain why the formation of
sand is a physical change.
Answer:
Sand is a form of physical change because it shows how one object is being worn out (broken down) into another object by nature.
Explanation:
Please answer correctly will give brainlist if correct
Before you kick a soccer ball you pull your leg back. For a brief moment, before you kick the ball, your leg is not moving as seen in the image below. At this point, your leg has______
Active Energy
Potential Energy
Conservation of Energy
Kinetic Energy
Answer:
Kinetic energy
Question 3 of 10
A 0.057 kg tennis ball and a tennis racket collide. The racket has an initial
momentum of -1.75 kg-m/s and a final momentum of -1.25 kg-m/s. The ball
has an initial momentum of 0.00684 kg-m/s. If you assume the collision is
elastic, what is the final velocity of the ball?
A. -0.50 m/s
B. -52.48 m/s
C. -2.99 m/s
d
D. -8.65 m/s
If we assume the collision to be elastic the final velocity of the ball will be -8.65 m/s, therefore the correct option is D.
What is elastic collision?It is a type of Collison for which the momentum, as well as the kinetic energy after and before the collision, is constant. there is no loss of energy in a perfectly elastic collision.
By using the law of conservation of momentum
momentum before collision = momentum after the collision
the initial momentum of rocket +initial momentum, of ball = final momentum of rocket + final momentum of the ball
By substituting the respective values
-1.75 + 0.00684 = -1.25 + m*v
-1.75 + 0.00684 = -1.25 + 0.057*v
v = -8.65 m/s
Thus, the final velocity of the ball is -8.65 m/s
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If a wave is traveling at a constant speed, and the frequency increases, what would happen to the wavelength?
It would increase
It would decrease.
It would remain constant.
It would drop to zero.
If a wave is traveling at a constant speed, and the frequency increases, the wavelength would decrease.
What is wavelength?The wavelength is the distance between the adjacent crest or trough of the sinusoidal wave. The wavelength is the reciprocal of the frequency of the wave.
Wavelength λ = 1 / frequency
The wavelength and frequency are inversely related to each other. So, when frequency is increased, the wavelength increases.
Thus, the wavelength of would decrease if the frequency increases.
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Answer:
B. It would decrease
Explanation:
A stone is thrown vertically upward with the velocity of 25 m/s. How long day
it take to reach the maximum height? Also calculate the height
Answer:
The stone takes 2.55 sec to reach a maximum height of 31.89 m
Explanation:
Vertical Motion
When an object is thrown vertically up with a speed vo, it loses speed because of the effect of the gravity and gains height until the speed is eventually zero. The height attained at that time is called maximum height, and can be calculated as follows:
[tex]\displaystyle h_m=\frac{v_o^2}{2g}[/tex]
Since vo=25 m/s
[tex]\displaystyle h_m=\frac{25^2}{2\cdot 9.8}=31.89\ m[/tex]
Also, the time taken to reach the maximum height is calculated by:
[tex]\displaystyle t_m=\frac{v_o}{g}[/tex]
[tex]\displaystyle t_m=\frac{25}{9.8}=2.55\ s[/tex]
The stone takes 2.55 sec to reach a maximum height of 31.89 m
Which Statement describes Newton's law of universal gravitation?
Mass has little effect on gravity between objects
gravity pushes objects away from Earth's center
gravity does not act between Earth and Moon
every object in the universe attracts every other objects
>You will get 100 points for answering this!
Answer:
The answer is D, every object in the universe attracts every other objects
Explanation:
Newton's law of universal gravitation is described as every object in the universe attracts every other objects.
What is gravitation?Gravitation is the force in physics that draws two masses together. Unbelievably, every single particle of matter in the cosmos attracts every other particle through gravity. The phrases gravitation and gravity are sometimes used synonymously to refer to the attraction that exists between everything with mass or energy.
According to Newton's Law of Universal Gravitation, every particle in the cosmos is drawn to every other particle with a force that is directly proportional to the product of their masses and inversely proportional to their distance from one another.
So, every object in the universe attracts every other objects describes Newton's law of universal gravitation.
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With what force will a car hit a tree if the car has a mass of 3,415 kg and it is accelerating at
a rate of 5 m/s2?
Answer:
[tex]F= 17,075\ N[/tex]
Explanation:
When the car is under an accelerating force and hits a tree, the instant force received by the tree is the same force that is accelerating the car.
The accelerating force can be calculated using Newton's second law:
[tex]F=m\cdot a[/tex]
Where m is the mass of the car and a is the acceleration.
[tex]F=3,415\ kg\cdot 5\ m/s^2[/tex]
[tex]\boxed{F= 17,075\ N}[/tex]
how is the process of finding the mass of a gas different from that of finding the mass of a liquid why is the difference necessary