Answer:
Explanation:
Current has speed vW with respect to the shore and boat has speed vB with respect to water or current so speed of boat with respect to shore
vW + vB .
Distance travelled with respect to shore by boat = D
time ( tout ) = distance / speed with respect to shore
tOut = D / ( vW + vB )
When the boat travels upstream , its velocity with respect to shore
= ( vB - vW ) , vB must be higher .
tin = D / ( vB - vW )
3 ) tin = D / ( vB - vW )
170 = 120 / (vB - 0.3 )
(vB - 0.3 ) = 12 / 17 = .706
vB = 1.006 m / s
4 )
tOut = D / ( vW + vB )
= 120 / ( .3 + 1.006 )
= 92.26 s
Time taken by a body is ratio of the distance traveled by it to the speed.
1)The expression for [tex]t{out}[/tex] is,[tex]t_{out}=\dfrac{D}{v_B+v_W}[/tex]
2)The expression for [tex]t{in}[/tex] is,[tex]t_{in}=\dfrac{D}{v_B-v_W}[/tex]
3) The speed of the boat with respect to the water is 1.006 m/s. 4) The time it takes the boat to move a distance D downstream is 91.9 seconds.What is upstream and downstream speed?
The net speed of the boat is upstream speed. The difference of the speed of the boat is downstream speed.
Given information-
The speed of the boat with respect to shore is [tex]v_w[/tex].
The speed of the boat in downstream with respect to water is [tex]v_B[/tex].
The distance traveled by the boat is [tex]D[/tex] in time [tex]t_{out}[/tex].
Time taken by a body is ratio of the distance traveled by it to the speed.
1) The net speed of the boat is upstream speed.As the distance traveled by the boat is [tex]D[/tex] in time [tex]t_{out}[/tex]. Thus,[tex]t_{out}=\dfrac{D}{v_B+v_W}[/tex]
2) The difference of the speed of the boat is downstream speed.As the distance traveled by the boat is [tex]D[/tex] in time [tex]t_{in}[/tex]. Thus,[tex]t_{in}=\dfrac{D}{v_B-v_W}[/tex]
Now the distance is 120 m, the value of [tex]t_{in}[/tex] is 170 s and [tex]v_W[/tex] 0.3 m/s. Thus,
3) The speed of the boat with respect to the water-Put the values in the formula obtains from the 2nd part of the problem,[tex]170=\dfrac{120}{v_B-0.3}\\v_B-0.3=\dfrac{120}{160} \\v_B=0.706+0.3\\v_B=1.006[/tex]
Hence the speed of the boat with respect to the water is 1.006 m/s.
4) The time it takes the boat to move a distance D downstream-Put the values in the formula obtains from the 1st part of the problem,[tex]t_{out}=\dfrac{120}{1.006+0.3}\\t{out}=\dfrac{120}{1.306} \\t{out}=91.9[/tex]
Hence the time it takes the boat to move a distance D downstream is 91.9 seconds.
Thus,
1)The expression for [tex]t{out}[/tex] is,[tex]t_{out}=\dfrac{D}{v_B+v_W}[/tex]
2)The expression for [tex]t{in}[/tex] is,[tex]t_{in}=\dfrac{D}{v_B-v_W}[/tex]
3) The speed of the boat with respect to the water is 1.006 m/s. 4) The time it takes the boat to move a distance D downstream is 91.9 seconds.Learn more about the upstream and downstream speed here;
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Galileo _____.
did not believe friction existed
believed that friction stopped objects in motion
believed that friction kept objects in motion
assumed that in a frictionless environment objects would never move
Answer:
friction help to slow motion in other word it oppose motion, but in a frictionless environment object would move with difficult stopping point.
How long will it take an object traveling at 90 kilometers per hour to travel 910 kilometers?
Explanation:
time = distance / velocity
We know that distance = 910 km and velocity = 90 km/h.
t = d / v
t = 910 km / 90 km/h
t = 10.11 hrs
The object traveled for 10.11 hours long. Hope this helps, thank you !!
Someone help please
Answer:
it would be downwards due to gravitational force
Drag the tiles to the correct boxes to complete the pairs
Match the particles with their characteristics.
subatomic particles with a positive charge
subatomic particles with a negative charge
subatomic particles with no charge
made of atoms
neutrons
electrons
protons
malaria
Answer:
1. Protons.
2. Electrons.
3. Neutrons.
4. Molecules.
Explanation:
1. Protons: subatomic particles with a positive charge. They are bound together in the nucleus of an atom due to strong nuclear forces.
2. Electrons: subatomic particles with a negative charge. Electrons can be defined as subatomic particles that are negatively charged and as such has a magnitude of -1.
3. Neutrons: subatomic particles with no charge. The negative charge of the electrons cancels the positive charge of the protons.
4. Molecules: they are made of atoms.
Generally, molecules attach on the inside of a mineral to give it shape. Therefore, the molecule of a mineral is a crystal three-dimensional regular structure (arrangement) of chemical particles that are bonded together and determines its shape.
Due to the fact that these molecules are structurally arranged or ordered and are repeated by different symmetrical and translational operations they determine the shape of minerals.
The blood pressure at your heart is approximately 100 mm Hg. As blood is pumped from the left ventricle of your heart, it flows through the aorta, a single large vessel with a diameter of about 2.5 cm. The speed of blood flow in the aorta is about 60 cm/s. Any change in pressure as blood flows in the aorta is due to the change in height: the vessel is large enough that viscous drag is not a major factor into successively smaller and smaller blood vessels until it reaches the capillaries. Blood flows in the capillaries at the much lower speed of approximately 0.7 mm/s. The diameter of capillaries and other small blood vessels is so small that viscous drag is a major factor..Because the flow speed in your capillaries is much less than in the aorta, the total cross-section area of the capillaries considered together must be much larger than that of the aorta. Given the flow speeds noted, the total area of the capillaries considered together is equivalent to the cross-section area of a single vessel of approximately what diameter?
a. 25 cm
b. 50 cm
c. 75 cm
d. 100 cm
Answer:
The correct option is c. 75 for this question
Explanation:
The correct option is c. 75 for this question:
Let's see how.
Continuity Equation is given as:
AcVc = AaVa
Where,
Aa = Area of Aorta
Ac = Area of the capillary
Va = Fluid speed in Aorta
Vc = Fluid speed in Capillary
So,
Assuming the fluid is the ideal one/
[tex]\pi[/tex]/4 [tex]Dc^{2}[/tex] Vc= [tex]\pi[/tex]/4 [tex]Da^{2}[/tex] Va
[tex]Dc^{2}[/tex] Vc= [tex]Da^{2}[/tex] Va
Dc = Da x [tex]\sqrt{\frac{Va}{Vc} }[/tex]
Dc = 2.5 cm x [tex]\sqrt{\frac{60 cm}{0.07 cm } }[/tex]
Dc = 73.192 cm
Dc = 75 approximately
Hence, the diameter of the capillary = 75 cm approximately
What is the velocity of the cart in these sections?
a-b
c-d
e-f
f-g
Plzzz help me with this
I’ll give brainliest
Answer:
(A) By reducing friction
Answer:
A
Explanation:
Which of the following choices is the best example of potential energy?
Answer:
A basketball sitting still in a players hands
Explanation:
The other 3 answers have the ball in motion (going towards the basket, bouncing, and rolling) so that would be kinetic energy.
When the basketball is sitting in the player's hands, it has the potential to be in motion.
Answer:
it is D not B it D
Explanation:
1. Three centimeters of water evaporated from a 200-hectare vertical walled reservoir during 24 hours. Storm water was added to the reservoir at a constant rate of 3 m3/s during this period. Determine the volume in ha-cm of water released during the period (through the bottom of the reservoir) if the water level was the same at the beginning and the end of the day.
Answer:
25920 ha-cm
Explanation:
Since water evaporates from the reservoir at a rate of 3 cm in 24 hours, its height changes at a rate of 3 cm/24 × 3600 s = 3 cm/86400s = 3.472 10⁻⁵ cm/s.
Now, the volume loss is dV/dt = dV/dh × -dh/dt
= dV/dt × -3.472 × 10⁻⁵ cm/s
= -3.472 × 10⁻⁵ cm/sdV/dh
The reservoir increases in volume at a rate of 3 m³/s = 3 × 10⁶ cm³/s in 24 hours.
So, the net rate of volume change per unit time of the reservoir is
3 × 10⁶ cm³/s - 3.472 × 10⁻⁵ cm/sdV/dh = Adh/dt where A = area of vertical walled reservoir and dh/dt = change in height of the reservoir with respect to time
So, 3 × 10⁶ cm³/s - 3.472 × 10⁻⁵ cm/sdV/dh = Adh/dt
Since dh/dt = 0 in 24 hours(since the water level remains the same after 24 hours, that is dh = 0)
3 × 10⁶ cm³/s - 3.472 × 10⁻⁵ cm/sdV/dh = Adh/dt
3 × 10⁶ cm³/s - 3.472 × 10⁻⁵ cm/sdV/dh = A × 0
3 × 10⁶ cm³/s - 3.472 × 10⁻⁵ cm/sdV/dh = 0
3.472 × 10⁻⁵ cm/sdV/dh = 3 × 10⁶ cm³/s
dV/dh = 3 × 10⁶ cm³/s ÷ 3.472 × 10⁻⁵ cm/s
dV/dh = 8.64 × 10¹¹ cm²
dV = (8.64 × 10¹¹ cm²)dh
Integrating both sides with V from 0 to V and h from h = 0 to h = 3 cm, we have
∫dV = ∫(8.64 × 10¹¹ cm²)dh
∫dV = (8.64 × 10¹¹ cm²)∫dh
V = (8.64 × 10¹¹ cm²)[h]₀³
V = (8.64 × 10¹¹ cm²)[3 cm - 0 cm]
V = (8.64 × 10¹¹ cm²)(3 cm)
V = 25.92 × 10¹¹ cm³
V = 2.592 × 10¹² cm³
V = 2.592 × 10¹² cm² × 1 cm
Since 1 ha = 10⁸ cm²,
V = 2.592 × 10¹² cm² × 1 ha/10⁸ cm² × 1 cm
V = 2.592 × 10⁴ ha-cm
V = 25920 ha-cm
A block of mass m = 150 kg rests against a spring with a spring constant of k = 880 N/m on an inclined plane which makes an angle of θ degrees with the horizontal. Assume the spring has been compressed a distance d from its neutral position.
Required:
a. Set your coordinates to have the x-axis along the surface of the plane, with up the plane as positive, and the y-axis normal to the plane, with out of the plane as positive.
b. Denoting the coefficient of static friction by μs, write an expression for the sum of the forces in the x-direction just before the block begins to slide up the inclined plane. Use defined quantities and g in your expression ΣFx = 25%
c. Assuming the plane is frictionless, what will the angle of the plane be, in degrees, if the spring is compressed by gravity a distance 0.1 m?
d. Assuming θ = 45 degrees and the surface is frictionless, how far will the spring be compressed, d in meters?
Answer:
b) k Δx - W cos θ - μ mg cos θ = m a , c) θ = 86.6º, d) Δx = 1.18 m
Explanation:
a) In the attachment we can see a diagram of the forces in this problem and the coordinate axes for its decomposition.
F is the force applied by the spring, while it is compressed, this force disappears when the block leaves the spring
b) Let's apply Newton's second law for when the spring is compressed
let's use trigonometry to break down the weight
sin θ = Wₓ / W
cos θ = W_y / W
Wₓ = W sin θ
W_y = W cos θ
Y axis
N - W_y = 0
N = W_y
N = W cos θ
X axis
F -Wₓ -fr = ma
the force applied by the spring is given by hooke's law
F = k Δx
friction force has the expression
fr = μ N
fr = μ W cos θ
we substitute
k Δx - W cos θ - μ mg cos θ = m a ( 1)
c) If the plane has no friction, what is the angle so that Δx = 0.1m
We write the equation 1, with fr = 0 and since the system is still a = 0
k Δx - W cos θ -0 = 0
cos θ = [tex]\frac{k \Delta x}{ m g}[/tex]
cos θ = [tex]\frac{880 \ 0.1}{ 150 \ 9.8}[/tex]
cos θ = 0.0598
θ = cos⁻¹ 0.0598
θ = 86.6º
d) In this part they give the angle θ = 45º and there is no friction, they ask the compression
the acceleration is zero, we substitute in 1
k Δx - W cos θ - 0 = 0
Δx = [tex]\frac{mg \ cos \ \theta}{k}[/tex]
Δx = [tex]\frac{ 150 \ 9.8 \ cos45}{880}[/tex]
Δx = 1.18 m
What are regular and irregular reflection of light? plz help its
urgent..
Explanation:
Regular reflection: It is the reflection from a smooth surface such that the light rays are evenly parallel to each other and an image is formed. ... Irregular reflection: It is the diffused reflection from uneven surface such that the light rays are not parallel to each other and do not form an image.
The electric field 30cm from a van de Graaff generator is measured to be 28,300N/C. What is the charge of the van de Graaf?
Answer:
14
Explanation:
EWAN KO LANG DIN BASTA YAN ALAM KO
What is the weight of a 44.5 kg object?
Answer:
98.11 I think
Explanation:
I really hope this helps have a wonderful day
The physics of wind instruments is based on the concept of standing waves. When the player blows into the mouthpiece, the column of air inside the instrument vibrates, and standing waves are produced. Although the acoustics of wind instruments is complicated, a simple description in terms of open and closed tubes can help in understanding the physical phenomena related to these instruments. For example, a flute can be described as an open-open pipe because a flutist covers the mouthpiece of the flute only partially. Meanwhile, a clarinet can be described as an open-closed pipe because the mouthpiece of the clarinet is almost completely closed by the reed.
Consider a pipe of length 80.0 cm open at both ends. What is the lowest frequency f of the sound wave produced when you blow into the pipe?
Answer:
Explanation:
Lowest frequency will be the fundamental frequency . For fundamental note
λ /2 = L where λ is wavelength of sound produced and L is length of open end pipe .
Given L = 80 cm
λ /2 = 80
λ = 160 cm .
= 1.6 m
frequency of note = velocity of sound / wavelength
= 330 / 1.6
= 206.25 Hz .
206 Hz approx.
Q5. Use Superposition to V. in the circuit below? (5 points)
4 mA
12V
2 ΚΩ
2 mA
1 ΚΩ
2 ΚΩ
Answer:
4va
12va
2jk
1jk
2jk
For PN junctions, determine if each statement below is True or False:
a. There can be large net current from p-side to n-side under forward bias.
b. There can be large net current from n-side to p-side under reverse bias if reverse bias is sufficiently high.
c. Electron diffusion current flows from n-side to p-side.
d. Electric field magnitude is higher under reverse bias
e. Electrons in the transition region drift from p-side to n-side.
Answer:
a) True
b) True
c) false
d) True
e) True
Explanation:
a) True
In forward bias, the resistance of the p–n junction reduces and hence the electric charges can flow easily.
b) True
In reverse bias condition, the electric current is due to the minority charge carriers (negative).
c) False
direction of diffusion current is in the direction of movement of positive charge i,e towards n side
d) True
Because the breakdown of charge carriers occur due to which the current increases rapidly
e) True
Which image represents a transverse mechanical wave?
Answer:
A
Explanation:
It is kinda like a spring.
The image which represents a transverse mechanical wave is A.
What is a mechanical wave?The wave has motion if all points on a wave vibrate at right angles to the direction of the wave propagation.
A transverse wave is a mechanical wave which is much like sinusoidal wave which has particles vibrating about their equilibrium position perpendicular to the direction of the motion of the wave.
Hence, the image which represents a transverse mechanical wave is A.
Learn more about mechanical wave.
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Plzzz answer this question correctly
Answer:
changing the direction in which a force is exerted
A vertical wire carries a current straight up in a region of the magnetic field directed north. What is the direction of the magnetic force on the current due to the magnetic field
Answer:
The direction of the force on the vertical wire is towards the East or right.
Explanation:
Using Fleming's right hand rule, the current is the middle finger pointing straight up, the magnetic field is the fore-finger pointing Northwards and then the thumb is the direction of the force on the vertical wire.
Following these conventions, the thumb points towards the East. So, the direction of the force on the vertical wire is towards the East or right.
Tell types of mirros and
each
one
Answer: We can identify the different types of mirrors without touching them by looking at the image it produces. Look into each mirror, the nature of the image produced will tell you the type of mirror it is.
- A plane mirror will produce an image of the same size as your face.
- A concave mirror will produce a magnified image of your face.
- A convex mirror will produce a diminished image of your face.
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What force causes a resistance in motion
when two surfaces are touching?
Answer:
FRICTION
Explanation:
Friction is a force, the resistance of motion when one object rubs against another.
Frictional force
Explanation:
Its the opposing force against horizontal motion
If 0.5 C charge passes through a wire in 10 seconds, what will be the value of the current flowing through the wire? *
20 mA
30 mA
50 mA
60 mA
Answer:
electric current passing through it will be 50mA
Explanation:
electric current = charge / time
I = Q / TI = 0.5 / 10 I = 0.05 amperecurrent = 0.05 A = 50mA
If 0.5C charge passes through a wire in 10 seconds, then 50mA current is flowing through the wire. Thus, the correct option is C.
What is Electric current?
Electric current is the flow of electricity in an electronic circuit. It is the amount of electricity flowing through a electronic circuit. It is generally measured in amperes (A). The larger the value in amperes, the more electricity is flowing in that circuit.
The formula for calculation of Electric current is:
I = Q/T
where, I = electric current,
Q = amount of charge,
T = time required
Therefore, the current flowing in the wire is:
I = 0.5C/ 10 seconds
I = 0.05 A or 50mA (1mA = 10⁻³A)
Therefore, the correct option is C.
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4. Kenny Kinematic notes that he is at mile marker 334 on the highway. He travels south to mile marker 181. What is his displacement?
Answer:
153miles
Explanation:
Distance on the highway = +334miles
Distance through south = -181miles (towards the negative direction)
Displacement will be the sum of the distances
Displacement = +334-181
Displacement = 153miles
Hence the displacement is 153miles
Which of the following diagrams would be a good, strong magnet?
How much force is needed to accelerate a Kia Soul with a
mass of 1200 kg to 5 m/s2?
Answer:
[tex]\boxed {\boxed {\sf 6,000 \ Newtons}}[/tex]
Explanation:
Force is the product of mass and acceleration.
[tex]F=ma[/tex]
The mass of the Kia Soul is 1200 kilograms and its acceleration is 5 meters per square second.
[tex]m= 1200 \ kg \\a= 5 \ m/s^2[/tex]
Substitute the values into the formula.
[tex]F= 1200 \ kg * 5 \ m/s^2[/tex]
Multiply.
[tex]F= 6000 \ kg*m/s^2[/tex]
1 kilgram meter per square second is equal to 1 Newton. Our answer of 6000 kg*m/s² equals 6000 N[tex]F= 6000 \ N[/tex]
Answer:
Given :-Mass = 1200 kgAcceleration = 5 m/s²To Find :-Force
Solution :-We know that
F = ma
F = Force
m = mass
a = acceleration
F = 1200 × 5
F = 6000 N
[tex] \\ [/tex]
A football quarterback runs 15.0 m straight down the playing field in 2.30 s. He is then hit and pushed 3.00 m straight backward in 1.74 s. He breaks the tackle and runs straight forward another 28.0 m in 5.20 s.
Calculate his average velocity (in m/s) for each of the three intervals. (Assume the quarterback's initial direction is positive. Indicate the direction with the sign of your answer.)
Answer:
6.52 m/s
1.72 m/s
5.38 m/s
Explanation:
this question requires us to find the average velocity.
1. velocity in straight down direction:
velocity = distance/time
= 15.0/2.30
= 6.52 m/s
2. velocity in straight backward direction:
velocity = distance/time
= 3.00 /1.74
= 1.72m/s
3. velocity in straight forward direction
velocity = distance/time
= 28.0/5.20
= 5.38 m/s
these are the his velocities for each if the intervals.
thank you!
A steel cylinder of length 10 cm, mass 160 g and density 8 g/em. The radius of the cylinder is
Answer:
0.8cm
Explanation:
Volume = mass/density = 160/8 = 20cm³
Volume = πr²h
r² = v/πh = 20/10π =0.64
r = √0.64 = 0.8
what is the relationship between net impulse and change in momentum?
Answer:
impulse equals the average net external force multiplied by the time this force acts. It is equal to the change in momentum.
Explanation:
What does a mass extinction look like in the fossil record?
O A. A layer of rock contains only fossils of living things that no longer
exist on Earth.
B. A layer of rock contains only fossils of species that presently exist
on Earth.
O C. A younger layer of rock contains a much greater variety of fossils
than a slightly older layer of rock does.
D. An older layer of rock contains a much greater variety of fossils
than a slightly younger layer of rock does.
Answer:
the answer is D
Explanation:
Mass extinctions were first identified by the obvious traces they left in the fossil record. ... Such dramatic changes in adjacent rock layers make it clear that mass extinctions were geologically rapid and suggest that they were caused by catastrophic events (e.g., a period of intense volcanic activity).
Mass extinction events wiped out many species at the same time resulting in older rock layers having more fossil variety than younger rock layers.
What are mass extinction events?Mass extinction events are events which resulted in the mass death of many species of organisms.
Mass extinction events are presumed to have occurred in the past as seen from gaps in the fossils records.
Mass extinction events are thought to have occurred through intense volcanic activity in a particular area.
A mass extinction event in the fossil record will show an older layer of rock containing a much greater variety of fossils than a slightly younger layer of rock does.
Therefore, mass extinction events wiped out many species at the same time.
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What is net force?
OA. a push or a pull
B. A measure of how fast an object is moving
OC. The amount of energy an object has
D. The combination of all forces acting on an object.
Answer:
D
Explanation:
The net force is the combination of all forces acting on an object.
