Answer:
Em₀ = U = m g h , Em_{f} = K = ½ m v²
Explanation:
When a car is on a ramp it has a certain amount of mechanical energy. At the highest point of the ramp the mechanical energy is fully potential given by
Em₀ = U = m g h
As part of this energy descends down the ramp, part of this energy is transformed into kinetic energy and has one part of each, even though the sum remains the initial energy
Em = K + U = ½ m v² + mg y
y <h
when it reaches the bottom of the ramp it has no height therefore there is no potential energy, all of it has been transformed into kinetic energy
Em_{f} = K = ½ m v²
This energy transformation is in the case that the friction force is zero.
If there is a friction force, it performs work against the low car, it is reflected in an increase in the internal energy (temperature) of the car. In this case the energy in the lower part is less than the initial one by a factor
[tex]W_{nc}[/tex] = - fr L
therefore the numeraire values of the velocity are lower, due to the energy lost by friction.
If an object is moving with a constant velocity to the right, what direction is the net force.
Group of answer choices
A.To the right
B.To the left
C.Net force is 0
D.Not enough information
Answer:
At constant velocity, his weight equals the force of friction. In other words, there is no net force. If however, he loosens his grip and decreases the friction force, he will accelerate downward.
Explanation:
Two boxes of masses 3M and 5M are attached by a massless rope. They are being pulled to the right with a constant force of P = 800 N, which allows them to just overcome static friction, with a μs= 0.70 between the floor and the boxes.
a. Find M.
b. Find the Tension in the rope between the two boxes.
Answer:
a) about 14.577 kg
b) 300 N
Explanation:
b) In order for the acceleration to be the same for each mass, the 800 N force must be divided between the boxes in proportion to their mass. That is, the net force on the 5M mass must be 5/8 of the total force, or 500 N. Then the tension in the rope is 800 N -500 N = 300 N, which is 3/8 of 800 N.
Tension: 300 N
__
a) The total mass is 8M, and the total normal force on the floor is ...
F = ma = (8M)(9.8 m/s^2)
The friction force is 0.7 times this, and is equal to the 800 N force pulling on the boxes.
800 N = (8M)(9.8 m/s^2)(0.7)
M = 800/(8·9.8·0.7) kg ≈ 14.577 kg
The Intensity level of a loud saw is 100 db at a distance of 5m. At what distance would the level be 80 db
Answer:
50 m
Explanation:
The relationship between the intensity of sound in dB and distance is given by the formula:
[tex]B_2=B_1+20log(\frac{R_1}{R_2} )\\\\Where \ B_2\ is \ the\ sound\ intensity\ at\ distance\ R_2\ and\\B_1\ is \ the\ sound\ intensity\ at\ distance\ R_1\ \\\\Given\ that: B_1=100\ dB, R_1=5\ m, B_2=80\ dB\\\\B_2=B_1+20log(\frac{R_1}{R_2} )\\\\80=100+20log(\frac{5}{R_2} )\\\\-20=20log(\frac{5}{R_2} )\\\\log(\frac{5}{R_2} )=-1\\\\\frac{5}{R_2}=10^{-1}\\\\\frac{5}{R_2}=0.1\\\\R_2=5/0.1=50\ m[/tex]
If the body with a mass of 4kg is moved by a force of 20 N, what is the rate of its acceleration?
Answer:
The answer is 5 m/s²Explanation:
The acceleration of an object given it's mass and the force acting on it can be found by using the formula
[tex]acceleration = \frac{force}{mass} \\[/tex]
From the question
force = 20 N
mass = 4 kg
We have
[tex]a = \frac{20}{4} \\ [/tex]
We have the final answer as
5 m/s²Hope this helps you
Pressure and temperature ______ with depth below Earth’s surface.
Answer:
Pressure increases as you move deeper below earth's surface.
Tempurature increases as you move deeper below earth's surface.
Hope this helps!
Explanation:
A crane uses a single cable to lower a steel girder into place. The girder moves with constant speed. The cable tension does work WT and gravity does work WG. Which statement is true
Explanation:
Work done by a force is given by :
[tex]W=Fd\cos\theta[/tex]
Where
F is force, d is displacement and [tex]\theta[/tex] is the angle between F and d.
In this problem, a crane is moving in downward direction, the force gravity is in downward direction and the tension is in upward direction.
We know that if force and displacement is in same direction, work is positive while if force and displacement is in oposite direction, work is negative.
I would mean that, [tex]W_g[/tex] is positive, because gravity is parallel to the displacement and [tex]W_t[/tex] is negative, because the tension is opposite to the displacement.
A 30%-efficient car engine accelerates the 1300 kg car from rest to 10 m/s . How much energy is transferred to the engine by burning gasoline
Answer:
The Energy transferred to the engine by burning gasoline = 216.67 KJ
Explanation:
The parameters given are:
The efficiency of the car engine, E = 30% = 0.3
Mass, m = 1300 kg
Initial velocity, u = 0, since the car is from rest
The final velocity, v = 10 m/s
Since the car was moving, we calculate its kinetic energy.
kinetic energy = ((1/2) (m) (v^2)
((1/2) (1300 kg) (10 m/s^2)
= 65,000 j
The Energy, Q transferred to the engine by burning gasoline in this case
= potential energy / The efficiency of the car engine, E
Q = 65,000 j / 0.3
= 216,666.66 J
Converting Joule to kilojoule
where 1KJ = 1000j
216,666.66 J = 216.67 KJ
A block of mass m begins at rest at the top of a ramp at elevation h with whatever PE is associated with that height. The block slides down the ramp over a distance d until it reaches the bottom of the ramp. How much of its original total energy (in J) survives as KE when it reaches the ground
This question is incomplete, the complete question is;
A block of mass m begins at rest at the top of a ramp at elevation h with whatever PE is associated with that height. The block slides down the ramp over a distance d until it reaches the bottom of the ramp.
How much of its original total energy (in J) survives as KE when it reaches the ground? m = 9.9 kg h = 4.9 m d = 5 m μ = 0.3 θ = 36.87°
Answer:
the amount of its original total energy (in J) that survives as KE when it reaches the ground will is 358.975 J
Explanation:
Given that;
m = 9.9 kg
h = 4.9 m
d = 5 m
μ = 0.3
θ = 36.87°
Now from conservation of energy, the energy is;
Et = mgh
we substitute
Et = 9.9 × 9.8 × 4.9
= 475.398 J
Also the loss of energy i
E_loss = (umg cosθ) d
we substitute
E_loss = 0.3 × 9.9 × 9.8 × cos36.87° × 5
= 116.423 J
so the amount of its original total energy (in J) that survives as KE when it reaches the ground will be
E = Et - E_loss
E = 475.398 J - 116.423 J
E = 358.975 J
The interaction between electrical energy and magnetism has been an important
topic in 20th century science, Which term describes this interaction?
Answer:
Maybe
Explanation:
I say maybe because it will help them still but not quite
A car which is traveling at a velocity of 15 m/s undergoes an acceleration of 6.5 m/s2 over a distance of 340 m. How fast is it going after that acceleration? (68.15 m/s)
v² - u² = 2 a ∆x
where u = initial velocity, v = final velocity, a = acceleration, and ∆x = distance traveled.
So
v² - (15 m/s)² = 2 (6.5 m/s²) (340 m)
v² = 4645 m²/s²
v ≈ 68.15 m/s
At an amusement park, a swimmer uses a water slide to enter the main pool. You may want to review (Pages 234 - 241) . Part A If the swimmer starts at rest, slides without friction, and descends through a vertical height of 2.81 m , what is her speed at the bottom of the slide
Answer:
Her speed at the bottom of the slide is 7.42 m/s
Explanation:
From the question,
The swimmer starts at rest, that is, her initial speed, u is 0 m/s.
Since she slides without friction and descends through a vertical height, then it is a free fall motion (due to gravity).
Also, from the question,
She descends through a vertical height of 2.81 m.
To determine her speed at the bottom of the slide, that is her final speed,
From one of the equations of motion for freely falling bodies
v² = u² + 2gh
Where v is the final speed
u is the initial speed
g is acceleration due to gravity (g = 9.8 m/s²)
and h is height
From the question,
u = 0 m/s
h = 2.81 m
Putting the values into the equation
v² = u² + 2gh
v² = 0² + 2×9.8×2.81
v² = 55.076
v =√55.076
v = 7.42 m/s
Hence, her speed at the bottom of the slide is 7.42 m/s.
Which famous Baroque period composer wrote 46 pieces of music while in jail?
Answer:
John Sebastian Bach
Answer:
Johann Sebastian Bach
Explanation:
please tell me if i am wrong! thank you!
Which two types of energy does a book have as it falls to the floor
Answer:
kinetic and potential energy
Explanation:
The power that a student generates when walking at a steady pace of vw is the same as when the student is riding a bike at vb = 3vw. The student is going to travel a distance d. The energy the student uses when walking is Ew. The energy the student uses when biking is Eb. The ratio EwEb is
Answer:
3
Explanation:
The first ionization potential for calcium (Z = 20, A = 40) is 6.11 eV. Singly-ionized calcium (Ca+) produces two very strong absorption lines in the Sun’s spectrum discovered by Joseph Fraunhofer in 1814, who named them "H" and "K" (he didn’t know they were from calcium, as this was >100 years before the development of quantum mechanics). Both lines always appear together, with lambda subscript H equals 3968 end subscript Å and lambda subscript K equals 3933 Å; hence they are called a "doublet
A. What is the speed of an electron that has just barely enough kinetic energy to collisionally ionize a neutral calcium atom? What is the speed of a calcium ion with this same kinetic energy?
B. What is the temperature T of a gas in which the average particle energy is just barely sufficient to ionize a neutral calcium atom?
C. The lower energy level of both lines is the ground state of Cat. What is the difference in energy in eV) between the two states that correspond to the upper energy levels of the Hand Klines, respectively? How does this compare to the energy of a calcium K photon? Can these two lines can be formed by transitions to upper energy levels with different principal quantum numbers (different n), or do they represent transitions with the same n but some different higher-order quantum number? Explain your reasoning based on your understanding of the general behavior of atomic energy levels (En).
Answer:
A) v = 1.47 10⁶ m / s, v = 0.5426 10⁴ m / s , B) T = 4.7 10⁴ K, C) n₂ = 42
Explanation:
A) For this part, let's calculate the speed of an electron that has an energy of 6.11 eV.
Let's reduce the units to the SI system
E₀ = 6.11eV (1.6 10⁻¹⁹ J / 1eV) = 9.776 10⁻¹⁹ J
The kinetic energy of the electron is
K = ½ m v²
E₀ = K
v = √ 2E₀ / m
v = √ (2 9.776 10⁻¹⁹ / 9.1 10⁻³¹)
v = √ (2.14857 10¹²)
v = 1.47 10⁶ m / s
now the speed of a calcium ion is asked, let's find sum
m = 40 1.66 10⁻²⁷ = 66.4 10⁻²⁷ kg
v = √ (2E₀ / M)
v = √ (2 9.776 10⁻¹⁹ / 66.4 10⁻²⁷)
v = √ (0.2994457 10⁸)
v = 0.5426 10⁴ m / s
B) the terminal energy of an ideal gas is
E = 3/2 kT
T = ⅔ E / k
T = ⅔ (9,776 10-19 / 1,381 10-23)
T = 4.7 10⁴ K
C) To calculate the energy of these lines we use the Planck expression
E = h f
where wavelength and frequency are related
c =λ f
f = c /λ
let's substitute
E = h c /λ
let's look for the energies
λ = 396.8 nm
E₁ = 6.63 10⁻³⁴ 3 10⁸ / 396.8 10⁻⁹
E₁ = 5.0126 10⁻¹⁹ J
λ = 393.3 nm
E₂ = 6.63 10⁻³⁴ 3 10⁸ / 3.93.3 10⁻⁹
E₂ = 5.0572 10⁻¹⁹ J
The difference in energy between these two states is
ΔE = E₂ -E₁
ΔE = (5.0572 - 5.0126) 10⁻¹⁹ J
ΔE = 0.0446 10⁻¹⁹ J
let's reduce eV
ΔE = 0.0446 10⁻¹⁹ J (1 eV / 1.6 10⁻¹⁹ J)
ΔE = 2.787 10⁻² eV
Now let's use Bohr's atomic model for atoms with one electron,
E = -13.606 Z² / n²
where 13,606 eV is the energy of the base state of the Hydrogen atom, Z is the atomic number of Calcium
n = √ (13.606 Z² / E)
λ = 396.8 nm
E₁ = 5.0126 10⁻¹⁹ J (1 eV / 1.6 10⁻¹⁹J) = 3.132875 eV
n₁ = √ (13.606 20² / 3.132875)
n₁ = 41.7
since n must be an integer we take
n₁ = 42
λ = 393.3 nm
E₂ = 5.0572 10⁻¹⁹ J (1eV / 1.6 10⁻¹⁹ J) = 3.16075 eV
n₂ = √ (13.606 20² / 3.16075)
n₂ = 41.5
Again we take n as an integer
n₂ = 42
We can see that the two lines have the same principal quantum number, so for the difference of these energies there must be other quantum numbers, which are not in the Bohr model, because of the small difference they are possibly due to small numbers of the moment angular orbital or spin
The boys are finally old enough to compete in the box car derby race at the local fair. They have been working on their cars since the conclusion of the race last year. One boy's car raced down the track and placed 2nd in his race. However, the other boy's car started well but half-way through the race a wheel came off and his car came to a complete stop. The boy was very disappointed and the other boy felt horrible for his friend. Which of the following graphs best represents the motion of boy's car that stopped?
5. A car advertisement states that a certain car can accelerate from rest to 70 m/s in 7
seconds. Find the car's average acceleration.
O-0.10 m/s^2
10 m/s^2
-10 m/s^2
O 0.10 m/s^2
Answer:
The car's average acceleration is [tex]10\ m/s^2[/tex].
Explanation:
Constant Acceleration Motion
It's a type of motion in which the velocity of an object changes by an equal amount in every equal period of time.
Being vo the initial speed, a the constant acceleration, vf the final speed, and t the time, the following relation applies:
[tex]v_f=v_o+at[/tex]
If we need to find the acceleration, we solve the above equation for a:
[tex]\displaystyle a=\frac{v_f-v_o}{t}[/tex]
The car accelerates from rest (vo=0) to vf=70 m/s in t=7 seconds. Substitute the values into the formula:
[tex]\displaystyle a=\frac{70-0}{7}=\frac{70}{7}=10[/tex]
[tex]a=10\ m/s^2[/tex]
The car's average acceleration is [tex]10\ m/s^2[/tex].
Note: The choices are not very clear, but the second choice seems to be the correct answer.
This diagram shows two different forces acting on a skateboarder. The
combined mass of the skateboard and the person is 81.5 kg. Based on this
information, what is the acceleration of the skateboarder?
Air resistance = 11.40 N
mi
Applied force = 52.80
A. 0.51 m/s2 to the left
O B. 1.94 m/s2 to the right
O C. 1.94 m/s2 to the left
O D. 0.51 m/s2 to the right
Answer:
Option D. 0.51 m/s² to the right.
Explanation:
The following data were obtained from the question:
Force applied (Fₐ) = 52.8 N
Force resistance (Fᵣ) = 11.4 N
Mass = 81.5 kg
Acceleration (a) =.?
Next, we shall determine the net force (Fₙ). This can be obtained as follow:
Force applied (Fₐ) = 52.8 N
Force resistance (Fᵣ) = 11.4 N
Net force (Fₙ) =?
Fₙ = Fₐ – Fᵣ
Fₙ = 52.8 – 11.4
Fₙ = 41.4 N to the right
Finally, we shall determine the acceleration of the skateboarder as show below:
Net force (Fₙ) = 41.4 N to the right
Mass = 81.5 kg
Acceleration (a) =..?
F = ma
41.4 = 81.5 × a
Divide both side by 81.5
a = 41.4 / 81.5
a = 0.51 m/s² to the right.
Thus, the acceleration of the skateboarder is 0.51 m/s² to the right.
Answer: .51 to the right
Explanation:
D
5. Mariam driving at a speed of 20.0 m/s applies
brakes close to a signal and travels a distance of
200 m before coming to rest. What was her
acceleration?
A. -0.50 m/s2
B. -0.70 m/s2
C. -1.00 m/s2
D. -2.00 m/s2
6. A trollen at rest is nushed to accelerate at a
Answer:
maibi.... D
Explanation:
I think is D
Question 4
Which of the following is unique for any given element?
O the mass of a neutron
o the number of neutrons
o the charge on the electons
O the number of protons
The coefficient of static friction between m1 and the horizontal surface is 0.50, and the coefficient of kinetic friction is 0.30. (a) If the system is released from rest, what will its acceleration be
This question is incomplete
Complete Question
m1 is 10kg, m2 is 4.0kg. The coefficient of static friction between m1 and the horizontal surface is 0.50. and the Coefficient of kinetic friction is 0.30.
a) if the system is released from rest what will be its acceleration
Answer:
0.7 m/s²
Explanation:
The coefficient of static friction between m1 and the horizontal surface is 0.50. and the coefficient of kinetic friction is 0.30.
(a) if the system is released from rest what will be its acceleration
g = acceleration due to gravity = 9.81 m/s²
Coefficient of Kinetic Friction = μk = 0.30
m1 = 10kg
m2 = 4.0kg
The formula to solve question a is given as:
a = acceleration at rest
m2g- μk m1g = (m1+ m2) a
Making a the subject of the formula:
a = (m2g- μk×m1g )/(m1+ m2)
a = [(4.0 kg × 9.81m/s²) – (0.30 ×9.81 × 10) ]/(10+4)
a = 0.7 m/s²
N₂ + H₂
NH3
how do i balance this equation?
Answer:
N2 + 3H2 -----> 2NH3
Explanation:
Reactants side:
2 Nitrogen
5 Hydrogen
Products Side:
2 Nitrogen
5 Hydrogen
If a rock is skipped into a lake at 24 m/s2, with that what force was the rock thrown if it was 1.75kg?
Answer: f= M×A
1.75kg×24= 42N
Explanation:
Because to find force you do Mass times acceleration so I did 1.75 kg times 24 would equal 42 Newtons!
a man weighing 490 n on earth weighs only 81.7 n on the moon. His mass on the moon is__kg. (Use g=9.8 m/s2
Answer:
m = 50 [kg]
Explanation:
In order to solve this problem we must be clear about the difference between weight and mass. Weight is the product of mass by the acceleration of the planet or the star. While the mass is always preserved it never changes regardless of where it is located.
So for the earth we have:
g = gravity acceleration = 9.8 [m/s^2]
m = mass [kg]
W = weigth = 490 [N]
therefore the mass will be:
m = W/g
m = 490/9.8
m = 50 [kg]
Now it is important to remember that the mass will be the same on the moon or on the earth, but the weight will be different, because the gravity acceleration of the moon is different from the gravity acceleration on earth
So the gravity on the moon is equal to:
81.7 = 50 * gm
gm = 1.634 [m/s^2]
What equation relates mechanical energy, thermal energy, and total energy when there is friction present in a system?
At which point on the image to the right would the ball have the greatest velocity if it moved from A to G.
please help me out.
A
B
C
D
E
F
G
Answer:
Total energy = Kinetic Energy + Potential Energy = Constant
Since the potential energy is lowest at point D the kinetic energy will be greatest at point D and the velocity will be the greatest.
Help me Please!!!!!!!
(A) Electricity and Magnetism
A). Three point charges are aligned along the x axis as shown in
Fig. Find the electric field at (a) the position (2, 0) and (b) the
position (0, 2).
electricity
Explanation:
the position (2,o
2. A bird flying horizontally at 10 m/s drops a branch. The bird is flying at an altitude of 20 m. Determine
the horizontal displacement it moves relative to where it was dropped.
Answer:
The horizontal displacement is 20 m.
Explanation:
Given that,
Velocity = 10 m/s
Height = 20 m
We need to calculate the time
Using equation of motion
[tex]s=ut+\dfrac{1}{2}gt^2[/tex]
Put the value into the formula
[tex]20=0+\dfrac{1}{2}\times9.8\times t^2[/tex]
[tex]t^2=\dfrac{20\times2}{9.8}[/tex]
[tex]t=\sqrt{\dfrac{20\times2}{9.8}}[/tex]
[tex]t=2.0\ sec[/tex]
We need to calculate the horizontal displacement
Using formula of horizontal displacement
[tex]\Delta x=v_{x}\times t[/tex]
Put the value into the formula
[tex]\Delta x=10\times2.0[/tex]
[tex]\Delta x=20\ m[/tex]
Hence, The horizontal displacement is 20 m.
Open Box. Consider a hollow box with the top missing. The sides have negligible thickness and each has length L and mass m. (a) Find the x-coordinate of the center of mass.
Answer:
x_{cm} = L / 2
Explanation:
The center of mass is defined by
[tex]x_{cm}[/tex] = 1 / M ∑ m_{i} x_{i}
where M is the total mass of the system
in this case the system is continuous so, for which we use the density
ρ = dm / dx
dm = ρ dx
substituting
x_{cm} = 1 / M ∫ x ρ dx
x_{cm} = ρ / M ∫ x dx
we integrate and evaluate from x = 0 to x = L
x_{cm} = ρ / M (L² /2 -0)
we introduce the density which is constant
ρ = M / L
x_{cm} = 1 /M (M/L) L² / 2
x_{cm} = L / 2