Answer:
b
Explanation:
convert heat energy into mechanical
A weightlifter holds a 1,500 N barbell 1 meter above the ground. One end of a 2-meter-long chain hangs from the center of the barbell. The chain has a total weight of 400 N. How much work (in J) is required to lift the barbell to a height of 2 m
Answer:
1800 J
Explanation:
We are given that
Weightlifter hold weight, w=1500N
Height of weightlifter from ground,h=1m
Length of chain=2m
Total weight of chain, w'=400 N
We have to find the work done required to lift the barbell to height of 2m.
Total work done=Work done to lift a barbell and half of the chain+ work done to lift the upper half of the chain
Total work done=[tex]1500+\frac{1}{2}(400)+\frac{1}{2}(400)(\frac{1}{2}(1))[/tex]
Total work done=[tex]1700+100[/tex]
Total work done=1800 J
Hence, work done is required to lift the barbell to a height of 2 m=1800 J
what kind of lens curve inward toward its center
Answer:
A concave lens is exactly the opposite with the outer surfaces curving inward, so it makes parallel light rays curve outward or diverge. That's why concave lenses are sometimes called diverging lenses.
Answer: A concave lens
A concave lens is exactly the opposite with the outer surfaces curving inward, so it makes parallel light rays curve outward or diverge. That's why concave lenses are sometimes called diverging lenses.
Hopes this helps :)
A swimmer, capable of swimming at a speed of 1.60 m/s in still water (i.e., the swimmer can swim with a speed of 1.60 m/s relative to the water), starts to swim directly across a 1.25-km-wide river. However, the current is 0.549 m/s, and it carries the swimmer downstream. (a) How long does it take the swimmer to cross the river
Answer:
t = 781.25 s
Explanation:
This is an exercise in velocity composition, if we set a reference system where the x-axis is perpendicular to the river and the y-axis is parallel to the river.
The swimmer has a velocity on the x axis
vx = 1.60 m / s
a velocity on the y axis, created by the current of the river
vy = 0.549 m / s
time is a scalar, therefore the time it takes to cross the river is the same time it creates the displacement in e; Axis y
X axis
vₓ = x / t
t = x / vₓ
t = 1250 / 1.6
t = 781.25 s
in this time a distance has descended
y = v_y t
y = 0.549 781.25
y = 428.9 m
Can you explain how newtons second law of force can be used in football and explain if possible
Answer:
Newtons 2nd Law of motion affects football as well. This law states the greater the mass of an object, the less the acceleration. This means that the more the objects weighs, the more difficult it is to move the object.
Explanation:
this is my best answer i can give you and mark me brainliest plz
Review Conceptual Example 6 as background for this problem. A car is traveling to the left, which is the negative direction. The direction of travel remains the same throughout this problem. The car's initial speed is 17.8 m/s, and during a 4.68-second interval, it changes to a final speed of (a)23.5 m/s and (b)15.3 m/s. In each case, find the acceleration (magnitude and algebraic sign).
Answer:
(a) 1.21 m/s² (b) 1.75 m/s²
Explanation:
The initial speed of the car, u = 17.8 m/s
Case 1.
Final speed of the car, v = 23.5 m/s
Time, t = 4.68-s
Acceleration = rate of change of velocity
[tex]a=\dfrac{23.5 -17.8 }{4.68}\\\\a=1.21\ m/s^2[/tex]
Case 2.
Final speed of the car, v = 15.3 m/s
[tex]a=\dfrac{23.5 -15.3}{4.68}\\\\a=1.75\ m/s^2[/tex]
Hence, this is the required solution.
Acceleration is the change in the velocity of a body with time.
What is acceleration?The term acceleration is the change in the velocity of a body with time. We have to find the acceleration in two separate cases;
Case 1;
a = -(23.5 m/s - 17.8 m/s)/4.68-s
a = -1.2 m/s^2
Case 2;
a = -(15.3 m/s - 17.8 m/s)/4.68-s
a = 0.53 ms-2
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is
5
The specific heat of copper is 0.385 J/g
°C. How much thermal energy is required
to increase the temperature of a 20g
sample of copper from 20°C to 50°C?
Q = m CAT
A 154 )
B 231 )
C 308 )
D 385 )
Answer:
Required energy Q = 231 J
Explanation:
Given:
Specific heat of copper C = 0.385 J/g°C
Mass m = 20 g
ΔT = (50 - 20)°C = 30 °C
Find:
Required energy
Computation:
Q = mCΔT
Q = 20(0.385)(30)
Required energy Q = 231 J
A horizontal force of 120N is required to push a block across a floor at constant velocity, what is the net force acting on the block?
Answer:
a horizontal force of 120N to Push the block into the floor is called net force
If a solid metal sphere and a hollow metal sphere of equal diameters are each given the same charge, the electric field (E) midway between the center and the surface is...A. greater for the solid sphere than for the hollow sphere.B. greater for the hollow sphere than for the solid sphere.C. zero for bothD. equal in magnitude for both, but one is opposite in direction from the other.
Answer:
C. zero for both
Explanation:
In case of solid metal sphere , when it is given any charge , all the charges are transferred on the surface and within surface no charge exists . In case of hollow metal sphere , all charges reside on surface . In this way , in both solid and hollow sphere , all charge reside on the surface and no charge resides inside it . Hence due to absence of any charge inside , there is no electric field inside the sphere in both the cases .
Hence in both the case electric field is zero .
option C is correct .
What does Fgrav or Fg mean when its next to a vector arrow?
Four people are pulling in different directions on a shopping cart. The magnitude of their pulling forces and the directions relative to straight east are indicated below. Jane: 80 pounds, straight east (0 degrees relative to east) Brittany: 100 pounds, north (90 degrees relative to east) Robyn: 80 pounds, southwest (225 degrees relative to east) Scott: 100 pounds, northwest (135 degrees relative to east)
Which way with the shopping cart go?
Answer:
17⁰ north of west
Explanation:
We shall represent forces by vector notations . i will represent unit vector towards east and j will represent unit vector towards north .
Jane: 80 pounds, straight east
F₁ = 80 i
Brittany: 100 pounds, north (90 degrees relative to east)
F₂ = 100 j
Robyn: 80 pounds, southwest (225 degrees relative to east ) or 45⁰ south of west
F₃ = - 80cos 45 i - 80 sin45 j = - 80/√2 x ( i + j )
= - 40√2 ( i + j )
Scott: 100 pounds, northwest (135 degrees relative to east) or 45⁰ west of north .
F₄ = - 100 cos 45 i + 100 sin45 j = 50√2 ( - i + j )
Resultant force
= F₁ + F₂ + F₃ + F₄
F = 80 i + 100 j + - 40√2 ( i + j ) + 50√2 ( - i + j )
F = 80 i - 90√2 i + 110√2 j
80 i - 127.26 i + 114.14 j
F = - 47.26 i + 114.14 j
Direction of force
TanФ = 114.14 / 47.26 = 2.4
Ф = 67⁰
67⁰ north of west .
Based on the data, which statement describes the most reliable way to
encode and transmit data and tells why?
A. Digital waves are more reliable because they are less likely to
change when copied.
B. Analog waves are more reliable because they include a range of
values like the original.
C. Analog waves are more reliable because they are less likely to
change when copied.
D. Digital waves are more reliable because they are slightly different
from the original.
Answer:it’s A. right for ape x
Explanation:
Based on data, digital waves are more reliable because they are less likely to change when copied (Option A).
What is a wave?A wave is a periodic distortion capable of traveling through a suitable media (either air or water).
The waves can be classified according to their direction into transversal and perpendicular.In conclusion, based on data, digital waves are more reliable because they are less likely to change when copied (Option A).
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If rider A is moving 8 meters per second, and rider B is moving 3 meters per second, how far away from rider A was rider B when first observed at the start of the graph?
Answer:
the answer is 32
Explanation:
he was riding pretty far
What is the average speed of a car that travels 60 meters in 2
seconds?
Answer:
30 m/s
Explanation:
Speed is distance over time. 60 meters / 2 seconds, = 30 m/s.
What is the speed of a train if it covers 69 km in 45
minutes.
Answer:
1.4km/h
Explanation:
distance/time = speed
69/45=1.4km/h
How fast would an object have to travel on the surface of Jupiter at the equator to keep up with the Sun (that is, so the Sun would appear to remain in the same position in the sky)? Use the facts that the radius of Jupiter is approximately 44,360 miles and its revolution is approximately 10 hours.
Answer:
27872.2 miles per hour
Explanation:
Given that :
Radius of Jupiter is approximately = 44,360 miles
Revolution is 10 hours ;
Jupiter makes one revolution in 10 hours :
Using the relation to obtain the velocity :
V = re
r = radius
w = 2π/T
Hence,
V = r * 2π/ T
V =44360 * 2 * π/10
V = 88720 * π/10
V = 278722.10 / 10
V = 27872.210
V = 27872.2 miles per hour
A DC motor connected to a switch-mode dc-dc converter goes into regenerative braking mode. The average current being supplied by the dc motor is 20 A. In the equivalent circuit of the dc motor, Ea=103 V, Ra=0.19 Ohms, and La=4 mH. Calculate the average power flow into the converter. Round answer to the nearest whole number.
Answer:
The correct answer is "2524 W".
Explanation:
The given values are:
Ia = 20 A
Ea = 103 V
Ra = 0.19 Ω
La = 4 mH
According to KVL,
⇒ [tex]V_0=E_a-I_aR_a[/tex]
On substituting the given values in the above equation, we get
⇒ [tex]=103-(20)(0.19)[/tex]
⇒ [tex]=103-3.8[/tex]
⇒ [tex]=126.2 \ V[/tex]
Now,[tex]=126.2\times 20[/tex]
The average power flow into the converter will be:
⇒ [tex]P=V_0 I_a[/tex]
On substituting the given values, we get
⇒ [tex]=(126.2\times 20)[/tex]
⇒ [tex]=2524 \ W[/tex]
A certain wave has a compressions and rarefactions.How should this wave be classified?
A) As a longitudinal wave
B)As a surface wave
C)A transverse wave
D)As an electromagnetic wave
This question involves the concepts of compression and rarefraction.
This wave should be classified as "A) a longitudinal wave".
Types of WaveA surface wave is a mechanical wave which propagates on the boundary interface between two different media.
A longitudinal wave is the wave in which the direction of travel of the wave and medium are the same. This wave consists of compressions and rarefactions.
A transverse wave is the wave in which the direction of travel of the wave and medium are perpendicular to each other. It consists of crests and troughs.
An electromagnetic wave is the one which consists of electric field and magnetic field vibrating perpendicular to each other.
Hence, the wave with compressions and rarefactions is classified as a longitudinal wave.
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What is the correct description for kinetic energy?Immersive Reader
(1 Point)
the energy an object has because of it temperature
the energy an object has because it is moving
the energy stored in an object because of its position
the energy stored in an object when you stretch or squash it
Answer:
The energy an object has because it is moving
Explanation:
It has been a while since I have talked about kinetic energy so I can't give you an explanation why that answer is right but it is.
A certain brand of hotdog cooker works by applying a potential difference of 144 V across opposite ends of a hot dog and allowing it to cook by means of the thermal energy produced. The current is 10.5 A, and the energy required to cook one hot dog is 60.6 kJ. If the rate at which energy is supplied is unchanged, how long will it take to cook three hot dogs simultaneously
Answer:
120.237 seconds
Explanation:
Given that:
V = 144 V
I = 10.5 A
H = 60.6 kJ
Using the formula:
H = I²RT
From H = I²RT; making T the subject, we have:
[tex]T = \dfrac{H}{I^2R}[/tex]
where;
[tex]R = \dfrac{V}{I}[/tex]
∴
[tex]T = \dfrac{H}{V \times I}[/tex]
[tex]T = \dfrac{60.6 \times 10^3 }{144 \times 10.5}[/tex]
T = 40.079
[tex]T_{neq} = 3T[/tex]
[tex]T_{neq} =3 \times 40.079[/tex]
[tex]\mathbf{T_{neq} =120.237 \ sec}[/tex]
In case A below, a 1 kg solid sphere is released from rest at point S. It rolls without slipping down the ramp shown, and is launched vertically into the air at point T. In case B, a 1 kg block slides without friction down an identically shaped ramp and is also launched vertically at point T. Select the statement that best describes which object will go higher after launch, and why
Answer:
the block reaches higher than the sphere
\frac{y_{sphere}} {y_block} = 5/7
Explanation:
We are going to solve this interesting problem
A) in this case a sphere rolls on the ramp, let's find the speed of the center of mass at the exit of the ramp
Let's use the concept of conservation of energy
starting point. At the top of the ramp
Em₀ = U = m g y₁
final point. At the exit of the ramp
Em_f = K + U = ½ m v² + ½ I w² + m g y₂
notice that we include the translational and rotational energy, we assume that the height of the exit ramp is y₂
energy is conserved
Em₀ = Em_f
m g y₁ = ½ m v² + ½ I w² + m g y₂
angular and linear velocity are related
v = w r
the moment of inertia of a sphere is
I = [tex]\frac{2}{5}[/tex] m r²
we substitute
m g (y₁ - y₂) = ½ m v² + ½ ([tex]\frac{2}{5}[/tex] m r²) ([tex]\frac{v}{r}[/tex])²
m g h = ½ m v² (1 + [tex]\frac{2}{5}[/tex])
where h is the difference in height between the two sides of the ramp
h = y₂ -y₁
mg h = [tex]\frac{7}{5}[/tex] ([tex]\frac{1}{2}[/tex] m v²)
v = √5/7 √2gh
This is the exit velocity of the vertical movement of the sphere
v_sphere = 0.845 √2gh
B) is the same case, but for a box without friction
starting point
Em₀ = U = mg y₁
final point
Em_f = K + U = ½ m v² + m g y₂
Em₀ = Em_f
mg y₁ = ½ m v² + m g y₂
m g (y₁ -y₂) = ½ m v²
v = √2gh
this is the speed of the box
v_box = √2gh
to know which body reaches higher in the air we can use the kinematic relations
v² = v₀² - 2 g y
at the highest point v = 0
y = vo₀²/ 2g
for the sphere
y_sphere = 5/7 2gh / 2g
y_esfera = 5/7 h
for the block
y_block = 2gh / 2g
y_block = h
therefore the block reaches higher than the sphere
[tex]\frac{y_{sphere}} {y_bolck} = 5/7[/tex]
Which type of electromagnetic radiation is most likely to cause sunburn?
A. Ultraviolet
B. Visible light
C. Infrared
D. X-rays
You are walking on a moving walkway in the airport. The length of the walkway is 59.1 m. If your velocity relative to the walkway is 2.35 m/s, and the walkway moves with a velocity of 1.85 m/s, how long will it take you to reach the other end of the walkway
Answer:
14.1seconds approx
Explanation:
Given data
Distance= 59.1m
Your velocity= 2.35m/s
Walkway velocity= 1.85m/s
Total velocity= 2.35+1.85= 4.2m/s
We know that
Velocity= distance/time
time= distance/velocity
substitute
time= 59.1/4.2
time= 14.07
time=14.1seconds approx
Hence the time is 14.1seconds approx
When observing the two diagrams, what is a concept shared by both?
Answer:
Convection
Explanation:
Convection refers to the transfer of heat by the actual movement of the heated molecules from the hot parts to the cooler parts.
Thus, the two diagrams show illustrate transfer of heat by the movement of molecules of a fluid.
This mode of heat transfer is known as convection. It is the concept illustrated by both diagrams.
Although the vocal tract is quite complicated, we can make a simple model of it as an open-closed tube extending from the opening of the mouth to the diaphragm, the large muscle separating the abdomen and the chest cavity. What is the length of this tube if its fundamental frequency equals a typical speech frequency of 230 Hz? Assume a sound speed of 350 m/s.
Answer:
0.76m
Explanation:
Given data
Frequency= 230Hz
speed= 350m/s
Since we are told that the frequency is the fundamental frequency n= 1
For a standing wave
Fn= nv/2L
n= 1
230= 1*350/2*L
230= 350/2L
cross multiply
2L= 350/230
2L=1.521
L=1.521/2
L=0.76m
Hence the length is 0.76m
If the solid, purple line represents a prey population
(e.g., rabbits) and the dashed, red line represents a predator population (e.g., coyotes), which of the following statements is a reasonable conclusion based on the graph?
Answer:
There is no correlation that can be made between the predator and prey populations.
Explanation:
Ermrmrm.
A place kicker must kick the football from a point [06] m from the goal and clear a bar 3.00 m above the ground. The ball leaves the ground with a speed of 20.0 m/s at an angle of 53.0 degrees above the horizontal. (a) By how much (m) does the ball clear (positive value) or fall short (negative value) of the cross bar? (This is vertical distance above or below the cross bar.) (b) When it gets to the cross bar, what is the vertical component of the ball’s velocity (m/s)? (Is it rising or falling-pay attention to the sign?)
Answer:
Explanation:
Horizontal component of initial velocity of throw = 20 cos 53 = 12 m /s
Vertical component = 20 sin 53 = 15.97 m /s
Distance to be travelled horizontally = 6 m .
time taken by ball to travel this distance = 6 / 12 = 0.5 s
vertical displacement during this period can be calculated as follows .
Initial vertical velocity = 15.97 m /s
time of travel = .5 s
acceleration = - 9.8 m /s²
s = ut - 1/2 g t²
= 15.97 x .5 - .5 x 9.8 x 0.5²
= 7.985 - 1.225
= 6.76 m
Goal post is 6 m high , so ball will cross the goal post .76 m or 76 cm above cross bar .
b ) vertical component of ball when it crosses the goal post . Let it be v .
v = u - gt
Applying this formula for vertical movement ,
v = 15.97 - 9.8 x .5
= 15.97 - 4.9
= 11.07 m /s .
An enclosure has an inside area of 50 m2, and its inside surface is black and is maintained at a constant temperature. A small opening in the enclosure has an area of 0.01 m2. The radiant power emitted from this opening is 48 W. What is the temperature of the interior enclosure wall, in K
Answer:
Explanation:
The enclosure will behave as black body . For black body , the formula for radiant energy is given by Stefan's law as follows
E = σ A T⁴ where σ = 5.67 x 10⁻⁸ W m⁻² T⁻⁴
Area A = .01 m²
E = 48 W
48 = .01 x 5.67 x 10⁻⁸ T⁴
T⁴ = 846.56 x 10⁸
T= 539 K
Following are the calculation to the temperature of the interior enclosure wall:
Given:
[tex]\to A_s=50\ m^2\\\\\to A_0=0.01\ m^2\\\\\to q_{rad}=48\ w\\\\\to \sigma = 5.67 \times 10^{-8}\ \frac{W}{m^{-2} T^{-4}} \\\\[/tex]
To find:
[tex]T_s=?[/tex]
Solution:
Using the value to calculate the surface is black radiates power:
[tex]\to q_{rad}=A_0 E_0 T_s\\\\\to q_{rad}=A_0 \sigma T_{s}^4\\\\\to 48=0.01 \times 5.67 \times 10^{-8} \times T_{s}^4\\\\[/tex]
[tex]\to T_{s}^4 =\frac{48}{0.01 \times 5.67 \times 10^{-8}} \\\\[/tex]
[tex]=\frac{48\times 100}{ 5.67 \times 10^{-8}} \\\\=\frac{48\times 100\times 10^{8} }{ 5.67 } \\\\=\frac{48\times 10^{10} }{ 5.67 } \\\\=8.46\times 10^{10} \\\\[/tex]
[tex]\to \bold{T_s=\pm 539.31 \ K}[/tex]
Therefore the final answer is "[tex]\bold{\pm 539.31 \ K}[/tex]".
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You are concerned about the moon roof on your new sports car. It seems to flex when driving at high speeds. Calculate how much net force the moon roof must withstand and in what direction. Assume the moon roof is flat with an area of 0.5 m^2 and the pressure and velocity over the moon roof is constant. Your driving speed is 20 m/s, and the velocity over the moon roof is 30 m/s. The pressure inside the car is 90,500 N/m^2 and the freestream pressure and density in front of the car are 90,000 N/m^2 and 1.1 kg/m^3.
Answer:
Explanation:
We shall apply Bernoulli's formula to solve the problem . It is as follows .
P + ρ gh + 1/2 ρ v² = constant .
P₁ + ρ gh + 1/2 ρ v₁² = P₂ + ρ gh + 1/2 ρ v₂²
P₁ + 1/2 ρ v₁² = P₂ + 1/2 ρ v₂²
P₁ - P₂ = 1/2 ρ (v₂² - v₁² )
= .5 x 1,1 ( 30² - 20² )
= 275 N / m²
velocity over moon roof is high , pressure will be lower there by 275 N / m²
Given pressure difference already existing = 90500 - 90000 = 500 N / m²
Additional pressure difference due to velocity difference = 275 N / m²
Total pressure difference = 275 + 500 = 775 N / m²
Area of roof = .5 m²
Total force acting upwards on the roof
= .5 x 775 N
= 387.5 N .
There is a very long straw of charge that is uniformly charged in electro static equilibrium. It has a charge per unit length of 4.0E-9 C/m (4.0 nC/m) and a radius of 0.5 m. What is the strength of the electric field a distance of 10.0 m from its center outside the straw
Answer:
2880 N/c
Explanation:
Given that:
Charge per unit length ; λ = 4 * 10^-9
radius, r = 10
Radius, R = 0.5m
Using the relation :
2λr / 4πE0R²
Columb's constant, k = 1/4πE0 =. 9* 10^9Nm²/C²
Hence, we have :
2λrk/ R²
(2 * 4 * 10^-9 * 10 * 9 * 10^9) / 0.5^2
(720 ÷ 0.25)
= 2880 N/c
Hearing rattles from a snake, you make two rapid displacements of magnitude 1.8 m and 2.4m. Draw sketches, roughly to scale, to show how your two displacements might add to give the following resultant of magnitudes.
a. 4.2 m
b. 0.6 m
c. 3.2 m
Answer:
The answer is a 4.2m
Explanation:
Given data
Please see attached the rough drawing for your reference.
From the drawing, you ran 18m west and 2.4m south
The displacement is
= 1.8+2.4
=4.2m
