The average marathon runner can complete the 42.2-km distance of the marathon in 3 h and 30 min. If the runner's mass is 85 kg, what is the runner's average kinetic energy during the run
Answer:
the runner's average kinetic energy during the run is 476.96 J.
Explanation:
Given;
mass of the runner, m = 85 kg
distance covered by the runner, d = 42.2 km = 42,200 m
time to complete the race, t = 3 hours 30 mins = (3 x 3600s) + (30 x 60s)
= 12,600 s
The speed of the runner, v = d/t
v = 42,200 / 12,600
v = 3.35 m/s
The runner's average kinetic energy during the run is calculated as;
K.E = ¹/₂mv²
K.E = ¹/₂ × 85 × (3.35)²
K.E = 476.96 J
Therefore, the runner's average kinetic energy during the run is 476.96 J.
Currents exist in the ocean without the need of electric fields.
True
False
Answer:
True
Explanation:
Sam, whose mass is 78 kg , stands at the top of a 11-m-high, 110-m-long snow-covered slope. His skis have a coefficient of kinetic friction on snow of 0.07. If he uses his poles to get started, then glides down, what is his speed at the bottom
Answer:
v = 8.09 m/s
Explanation:
For this exercise we use that the work done by the friction force plus the potential energy equals the change in the body's energy.
Let's calculate the energy
starting point. Higher
Em₀ = U = m gh
final point. To go down the slope
Em_f = K = ½ m v²
The work of the friction force is
W = fr L cos 180
to find the friction force let's use Newton's second law
Axis y
N - W_y = 0
N = W_y
X axis
Wₓ - fr = ma
let's use trigonometry
sin θ = y / L
sin θ = 11/110 = 0.1
θ = sin⁻¹ 0.1
θ = 5.74º
sin 5.74 = Wₓ / W
cos 5.74 = W_y / W
Wₓ = W sin 5.74
W_y = W cos 5.74
the formula for the friction force is
fr = μ N
fr = μ W cos θ
Work is friction force is
W_fr = - μ W L cos θ
Let's use the relationship of work with energy
W + ΔU = ΔK
-μ mg L cos 5.74 + (mgh - 0) = 0 - ½ m v²
v² = - 2 μ g L cos 5.74 +2 (gh)
v² = 2gh - 2 μ gL cos 5.74
let's calculate
v² = 2 9.8 11 - 2 0.07 9.8 110 cos 5.74
v² = 215.6 -150.16
v = √65.44
v = 8.09 m/s
which of the following can cause skin cancer and which can't?
Campfire
Flashlight
Lamp
Sun
Tanning bed
fluorescent light bulbs
Is water a element or compound
Answer:
compound
Explanation:
water is made up of oxygen (O) and hydrogen (H) therefore making it a compound (H2O)
which form of energy is an example of kinetic energy
Answer:
1. realizing of arrow
2. kicking of ball
3. punching the punching bag
Potential energy is
stored in a state of readiness.
conserved.
energy of motion.
not measurable.
Answer:
stored in a state of readiness.
Explanation:
Potential energy is stored in a state of readiness.
Potential energy can be defined as an energy possessed by an object or body due to its position.
Mathematically, potential energy is given by the formula;
[tex] P.E = mgh[/tex]
Where, P.E represents potential energy measured in Joules.
m represents the mass of an object.
g represents acceleration due to gravity measured in meters per seconds square.
h represents the height measured in meters.
A hot piece of copper is placed in water in an insulated cup. What is the final
temperature of the water and copper?
(Use
me AT: + copperfcoppe, Acoppe: = 0]
m = 0.50 kg water = 4.18 kJ/kg-'c,
m.copper = 0.50 kg, Cropper = 0.386 kJ/kg-°C, Ti copper = 115°C
Tower = 22°C
O A. 30°C
B. 45°C
O C. 39°C
O D. 52°C
Answer:
38.7 °C.
The final temperature (reached by both copper and water) is 38.7 °C.
So the answer is probably C.
The heat energy lost by the metal piece is equal to the heat gained by the water in the cup. From this concept using calorimetric equation, their final temperature is equal to 30°C.
What is calorimetric equation?Calorimetric equation states the relation between heat energy absorbed or released by a system with the mass, specific heat capacity and temperature difference of the matter as written below:
q = m c Δ
Given, mass of copper piece = 0.50 kg
mass of water = 0.50 kg
c for Cu = 0.386 KJ/Kg °C
c for water = 0.418 KJ/Kg °C
The heat energy lost by copper metal is equal to the heat energy gained by water. Let T be the final temperature.
then,
0.50 kg × 0.386 KJ/Kg °C × (115°C - T) = 0.50 kg × 0.418 KJ/Kg °C × (T - 22°C).
2.09 (115°C - T) = 0.193 (T - 22°C).
2.09 T - 45.98 + 0.193 = 22.195
T = 30°C
Therefore, the final temperature of water and copper piece is 30 °C.
Find more on calorimetry:
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How/is climate change/human interaction affecting mutualism
How does the size of a wind turbine affect its energy output?
A.)Smaller turbines spin slower.
B.) Larger turbines have a greater storage capacity.
C.) Larger turbines generate more electricity.
D.)Smaller turbines are better for capturing strong winds.
Answer:
Larger tubines generate more electricity.
Explanation:
Larger blades allow the turbine to capture more of the kinetic energy of the wind by moving more air through the rotors. However, larger blades require more space and higher wind speeds to operate. This distance is necessary to avoid interference between turbines, which decreases the power output.
Calculate the magnetic field at 2m from a straight wire carrying a current of 5 A. (K = 2 x 10 ^-7)
Answer:
[tex]B=5\times 10^{-7}\ T[/tex]
Explanation:
Given that,
Current in a wire, I = 5 A
We need to find the magnetic field at 2m from a straight wire carrying a current of 5 A.
The magnetic field due to a wire is given by :
[tex]B=\dfrac{\mu_0I}{2\pi r}\\\\B=\dfrac{4\pi \times 10^{-7}\times 5}{2\pi \times 2}\\\\B=5\times 10^{-7}\ T[/tex]
So, the required magnetic field is [tex]5\times 10^{-7}\ T[/tex].
The power in our homes and buildings cycles at a frequency of 60Hz. If someone accidentally dropped a power line into a holding tank for frogs their muscles would immediately become stiff. This is because the high frequency stimuli is causing
Answer:
The answer is "Rigor mortis".
Explanation:
When the very large volume will be that the progress of its postponed by calcium and magnesium. The causes brain intensification of a liver due to the change throughout the myofibrils within a week of dying of its organism. When anyone accidentally spilled a power cable into a rank for toads, one's tissue will be disrupted instantly by stringent deaths.
This is because the high frequency stimuli of the power line is causing rigor
mortis.
Rigor mortis is referred to as the stiffening of the body of animals when they
die and is usually caused by the body's glycogen and ATP concentration
diminishing.
Rigor mortis can also be caused by a high frequency stimuli such as
exposure to electric current which hastens the conditions that causes it to
occur.
Read more on https://brainly.com/question/25435810
3. Batteries create electricity and generators create electricity. *
True
False
Give 2 examples of situations in which environmental values could come into conflict with other values
Answer:
Example of situations in which environmental values could come into conflict with other values, such as economy values of family values, include deciding whether or not a businessman should fly across the country for a meeting or whether a family should buy a gas car or an electric car.
student builds a simple circuit with a single resistor with resistance R and measures an electric potential difference ΔV across the resistor. Then, the student replaces the resistor with a new one of resistance 2R and keeps the electric potential difference the same. What is the current (I2) through the new circuit in terms of the original current(I1)? 6mks
Answer:
i₂ = ½ i₁
Explanation:
Let's write ohm's law for the first statement
V = i₁ R
i₁ = V / R
tells us that we change the resistance to R '= 2R
let's write ohm's law
V = i₂ R’
indicates that V remains constant
i₂ = V / R '
i₂ = V / 2R
i₂ = ½ V/R
we substitute
i₂ = ½ i₁
A spherical shell with a net charge of 3Q surrounds a point charge of -q at the center of the shell. The charges on the inner and outer surfaces of the shell are:
Answer:
1) The charge on the outer shell is +4·Q
2) The charge on the inner shell is +Q
Explanation:
1) The given parameters of the spherical shell are;
The net charge on the spherical shell = 3·Q
The point charge surrounded by the spherical shell = -Q
Let 'x' represent the charge on the outer shell, and let 'y', represent the charge on the inner shell, we have;
The net charge, 3·Q = -q + x
∴ x = 3·Q + Q = 4·Q
The charge on the outer shell, x = 4·Q
2) The net charge in the shell is zero, therefore, the charge on the inner shell, 'y', is given as follows;
-Q + y = 0
∴ y = +Q
The charge on the inner shell, y = +Q
Help with question I’ll mark brainliest
The three inclines have the same height and they are all frictionless, but they have different angles. Which object will have the highest speed at the bottom of the incline
Answer:
the speed of the body must be the same for the three hills regardless of their slope
v = [tex]\sqrt{2gy}[/tex]
Explanation:
To shorten the answer to this exercise, let's use the concept of conservation of energy
starting point. Highest point of the hill
Em₀ = U = m h y
final point. Lower part of the hill
Em_f = K = ½ m v²
as there is no friction the mechanical energy is conserved
Em₀ = Em_f
mg y = ½ m v²
v = [tex]\sqrt{2gy}[/tex]
Let's analyze this result, we see that the speed at the bottom of the hill depends only on the height of the hill, not on the slope, so the speed of the body must be the same for the three hills regardless of their slope
fasttt plsss!!!!
Energy A car engine drives a generator, which produces and stores electric charge in the car's battery. The headlamps use the electric charge stored in the car battery. List the forms of energy in these three operations
llustration 2: Aman can run a distance of 100 m in 20 seconds. Find the speed of Aman in m/s.
Answer:
[tex]\boxed {\boxed {\sf 5 \ meters/second}}[/tex]
Explanation:
Speed is equal to distance over time.
[tex]s=\frac{d}{t}[/tex]
The distance is 100 meters and the time is 20 seconds.
[tex]d= 100 \ m \\t= 20 \ s[/tex]
Substitute the values into the formula.
[tex]s=\frac{100 \ m }{20 \ s}[/tex]
Divide.
[tex]s= 5 \ m/s[/tex]
Aman's speed is 5 meters per second.
Two coils have the same number of circular turns and carry the same current. Each rotates in a magnetic field acting perpendicularly to its axis of rotation. Coil 1 has a radius of 4.5 cm and rotates in a 0.21-T field. Coil 2 rotates in a 0.39-T field. Each coil experiences the same maximum torque. What is the radius (in cm) of coil 2
Answer:
Explanation:
Torque acting on a coil in a magnetic field = MBsinθ where M is magnetic moment , B is magnetic field and θ is inclination of the normal to coil with direction of field.
For maximum torque sinθ = 1
Maximum torque = MB
M = NIA where N is no of turns , I is current and A is area of the coil
Maximum torque = NIAB
As maximum torque is same
N₁I₁A₁B₁ = N₂I₂A₂B₂
N₁ = N₂ , I₁ = I₂
A₁B₁ = A₂B₂
π R₁² B₁ = π R₂² B₂
4.5² x .21 = R₂² x .39
R₂² = 10.9
R₂ = 3.3 cm .
The skater lowers her arms as shown in the adjacent
figure decreasing her radius to 0.15 m. Find her new speed.
Answer:
is there more?
Explanation:
7. Consumers can be predators, prey, scavengers, herbivores omnivoree, or carnivore: What is the common characteristic of all consumer: A Create their own food B. Must eat to get energy C. Hunt for live animals D. Will eat anything
Answer:
B. Must eat to get energy
Explanation:
The common characteristics of all consumers is that they must eat to get energy. This way, they are termed heterotrophs.
Heterotrophs are organisms that cannot make their own food. They must eat other organisms to obtain nutrition for energy needs.
Plants do not do this. They are autotrophs in that they simply make their own food.
They use this food to obtain energy for their living activities.
uniform acceleration means the velocity of the body is either increasing or decreasing changing at a constant rate TRUE OR FALSE? thank youu
Answer:
False.
Explanation:
In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.
This simply means that, acceleration is given by the subtraction of final speed from the initial speed all over time.
Hence, if we subtract the final speed from the initial speed and divide that by the time, we can calculate an object’s acceleration.
Mathematically, acceleration is given by the equation;
[tex]Acceleration (a) = \frac{initial speed - final speed}{time}[/tex]
[tex]a = \frac{v - u}{t}[/tex]
Where,
a is acceleration measured in [tex]ms^{-2}[/tex]
v and u is initial and final speed respectively, measured in [tex]ms^{-1}[/tex]
t is time measured in seconds.
Additionally, acceleration is a vector quantity because it has both magnitude and direction.
Hence, uniform acceleration means the velocity of the body is increasing at a constant rate. For example, an object or body that is experiencing a free fall in a uniform gravitational field is said to be in uniform acceleration.
The water side of the wall of a 60-m-long dam is a quarter-circle with a radius of 7 m. Determine the hydrostatic force on the dam and its line of action when the dam is filled to the rim. Take the density of water to be 1000 kg/m3.
Answer:
[tex]26852726.19\ \text{N}[/tex]
[tex]57.52^{\circ}[/tex]
Explanation:
r = Radius of circle = 7 m
w = Width of dam = 60 m
h = Height of the dam will be half the radius = [tex]\dfrac{r}{2}[/tex]
A = Area = [tex]rw[/tex]
V = Volume = [tex]w\dfrac{\pi r^2}{4}[/tex]
Horizontal force is given by
[tex]F_x=\rho ghA\\\Rightarrow F_x=1000\times 9.81\times \dfrac{7}{2}\times 7\times 60\\\Rightarrow F_x=14420700\ \text{N}[/tex]
Vertical force is given by
[tex]F_y=\rho gV\\\Rightarrow F_y=1000\times 9.81\times 60\times \dfrac{\pi 7^2}{4}\\\Rightarrow F_y=22651982.59\ \text{N}[/tex]
Resultant force is
[tex]F=\sqrt{F_x^2+F_y^2}\\\Rightarrow F=\sqrt{14420700^2+22651982.59^2}\\\Rightarrow F=26852726.19\ \text{N}[/tex]
The hydrostatic force on the dam is [tex]26852726.19\ \text{N}[/tex].
The direction is given by
[tex]\theta=\tan^{-1}\dfrac{F_y}{F_x}\\\Rightarrow \theta=\tan^{-1}\dfrac{22651982.59}{14420700}\\\Rightarrow \theta=57.52^{\circ}[/tex]
The line of action is [tex]57.52^{\circ}[/tex].
Two wires each carry 10.0 A of current (in opposite directions) and are 2.50 mm apart. What is the magnetic field 37.0 cm away at point P, in the plane of the wires
Answer:
see answer below
Explanation:
Before we do any kind of calculation, we need to convert the proper units of the exercise. All the units of distance must be in meters, so, let's change distance of the wire, and the magnetic field to meters:
Separation between the wires are 2.5 mm:
2.5 mm * (1 m / 1000 mm) = 0.0025 m
The distance of P from the bottom of the wires is 37 cm:
37 cm * (1 m/100 cm) = 0.37 m
The distance of P from the top of the wires is just the sum of the two distances:
R = 0.37 + 0.0025 = 0.3725 m
Now that we have the distance, we can determine the magnetic field, using the following expression:
B = B(bottom) - B(top) or just B₂ - B₁
And B = μ₀ I / 2πR
Replacing in the above expression we have:
B = μ₀ I / 2π ( 1/R₂ - 1/R₁)
Now we can determine the magnetic field:
B = (4πx10⁻⁷ * 10 / 2π) (1/0.37 - 1/0.3725)
B = 3.63x10⁻⁸ TWhich means that the magnetic field is out of the page.
Hope this helps
can you please tell me what this is
Answer:
200000 J
Explanation:
From the question given above, the following data were obtained:
Mass (m) of roller coaster = 1000 Kg
Velocity (v) of roller coaster = 20 m/s
Kinetic energy (KE) =?
Kinetic energy is simply defined as the energy possess by an object in motion. Mathematically, it can be expressed as:
KE = ½mv²
Where
KE => is the kinetic energy.
m =>is the mass of the object
V => it the velocity of the object.
With the above formula, we can obtain the kinetic energy of the roller coaster as follow:
Mass (m) of roller coaster = 1000 Kg
Velocity (v) of roller coaster = 20 m/s
Kinetic energy (KE) =?
KE = ½mv²
KE = ½ × 1000 × 20²
KE = 500 × 400
KE = 200000 J
Therefore, the kinetic energy of the roller coaster is 200000 J.
Learning Task 5: Read each situation and encircle the letter of the best
answer. Do this activity on your notebook,
1. Our team is the champion because of our captain. No matter how fast his
Opponent shoot the ball he can do the same, he never misses it and hits it
right back. What emotion is shown in the situation?
A. Happiness
B. Anger
C. Sadness
D. Afraid
Answer:
I think the tone is happiness using the clues of "champion". But depending on who is saying it and background information it could be something different but based on the text here and the answer choices personally the best answer in my opinion is happiness.
If there was jealousy or optimism it would be a harder decision.
Explanation:
Hope this helped :)
I can give you 50 points.
Freddy is participating in a pumpkin lifting contest. The 68 kg pumpkin starts at rest on the ground. If Freddy exerts a 720N force on the pumpkin, what is the acceleration of the pumpkin as he lifts it off the ground?
Draw a Force Diagram for the pumpkin. Indicate the direction of the sum of the forces.
Draw a Motion Diagram for the pumpkin. Is your motion diagram consistent with your force diagram?
Use Newton’s 2nd Law to find the pumpkin’s acceleration.
Answer:
Freddy is participating in a pumpkin lifting contest. The 68 kg pumpkin starts at rest on the ground. If Freddy exerts a 720N force on the pumpkin, what is the acceleration of the pumpkin as he lifts it off the ground?
Explanation:
An object has a coefficient of static friction of 0.3 and a normal force of 30 N. Find the force of static friction.
Answer:
9N
Explanation:
static friction=normal force x coefficient of static friction
so static friction =30N x 0.3= 9N
Explanation:
9N is the static friction