Answer:
3.7 km/h
Explanation:
Let's call v the proper speed of the boat and v' the speed of the water in the river.
When the boat travels in the direction of the current, the speed of the boat is:
v + v'
And it covers 50 km in 3 h, so we can write
[tex]v+v' = \frac{50 km}{3 h}=16.7 km/h[/tex] (1)
When the boat travels in the opposite direction, the speed of the boat is
v - v'
And it covers 50 km in 5.4 h, so
[tex]v-v'=\frac{50 km}{5.4 h}=9.3 km/h[/tex] (2)
So we have a system of two equations: by solving them simultaneously, we find the value of v and v':
[tex]v+v'=16.7 \\v-v'=9.3[/tex]
Subtracting the second equation from the first one we get:
[tex](v+v')-(v-v')=16.7-9.3\\2v'=7.4\\v'=3.7[/tex]
So, the speed of the water is 3.7 km/h.
The history of Sir Isaac Newton’s study of gravity does which of the following?
A. Illustrates how a theory becomes a law
B. Provides an example of a theory that has been discredited
C. Demonstrates the importance of gravity in marine science
D. Shows that theories have long been an important part of science
A. Illustrates how a theory becomes a law
Answer:
A. Illustrates how a theory becomes a law
Explanation:
Newtons studied about the gravity for a very long time and proposed theory about it.
Later on, based on his theories comes the gravitational law. His theory were based on various assumptions and examples that he related to explain the structure of universe.
His work shows how theories can become laws which are universally obeyed.
in the problem below, what is the student showing?
[tex]3 \times 3 \times 3 = 27 {cm}^{3} [/tex]
Answer:
Student showing the volume of cube
V = a³
if a = 3 cm
Then volume is a³ = 3 ×3 × 3
= 27 cm³
Edson exercises in sets that are each t minutes long. He does 6 sets of push-ups, 3 sets of pull-ups, and 4 sets of sit-ups. Use an expression to represent the time it takes Edson to exercise as the sum of three different terms. Simplify the expression. Enter your answer in the box. The time it takes Edison to exercise is equal to t.
edson takes 130 minutes of exersise
step by step answer:
10 x 13 = 130
Answer:
The expression would be 13t.Explanation:
We know that:
Each set takes t minutes to be done.Edson does three types of exercises with different sets: 6, 3 and 4.Basically, we have to multiply each set by t minutes.
We have:
6 sets of push-ups: t + t + t + t + t + t = 6t3 sets of pull-ups: t + t + t = 3t4 sets of sit-ups: t + t + t + t = 4tThe total amount of time considering all sets is 6t + 3t + 4t = 13t. In other words, Edson did 13 sets, if one set takes t minutes, then the 13 sets takes 13t minutes.
2in+3in+4in+4in+6in+7in calculate the area and perimeter of each shape
Answer:
Let "a", "b" and "с" be sides of the triangle ("с" is the longest side).
The triangle will be:
right if a² + b² = c²
аcute if a² + b² > c²
obtuse if a² + b² < c²
a.
a=3, b=4 and c=5
a² + b² = 3² + 4² = 9 + 16 = 25 and c² = 5² = 25
25 = 25 ⇒ right triangle.
b.
a=5, b=6 and c=7
a² + b² = 5² + 6² = 25 + 36 = 61 and c² = 7² = 49
61 > 49 ⇒ аcute triangle.
c.
a=8, b=9 and c=12
a² + b² = 8² + 9² = 64 + 81 = 145 and c² = 12² = 144
145 > 144 ⇒ аcute triangle.
The two waves shown here are the same distance from point X and are traveling toward each other.
What is the amplitude of the resulting wave when the two waves meet at point X?
0.0 cm
1.0 cm
2.0 cm
4.0 cm
Figure missing to find amplitude
Here I try to explain, to find amplitude.
It is the maximum displacement of the wave. The resultant amplitude of two inferring waves is equal to sum of those two waves displacements at the same location. If they are in opposite direction destructive inference occurs.
Answer:
The answer to your question is 0.0 cm
To determine the speed of a wave, you must know the waves wavelength and_____
You must know the wavelength and the frequency.
A 1500.0 kg car hits a brick wall with a force of 60.0 N in 1.75 seconds. What is the change in the momentum of the car?
Answer:
Change in the momentum of the car = 105 kgm/s
Explanation:
We have the Newton's second law, that is rate of change of momentum is force.
[tex]\frac{dP}{dt}=F\\\\\frac{mv-mu}{dt}=F\\\\mv-mu=Fdt[/tex]
That is rate of change of momentum is impulse.
Here we need to find rate of change of momentum = Fdt
dP = Fdt
dP = 60 x 1.75 = 105 kgm/s
Change in the momentum of the car = 105 kgm/s
The electromagnetic waves that have the lowest frequencies are called a. radio waves. c. ultraviolet waves. b. microwaves. d. x-rays. Please select the best answer from the choices provided A B C D
the answer to that would be radio waves which would be answer A
what type of motion does an object traveling in a horizontal vector have?
Accelerating objects are objects which are changing their velocity - either the speed (i.e., magnitude of the velocity vector) or the direction. An object undergoing uniform circular motion is moving with a constant speed. Hope you find this helpful
Define the term “force”.
Energy that is applied to an object.
--TheOneandOnly003
The Jedi have the force. it flows through all things. Joking it will change the motion of an object
Which law describes the magnetic field in a nonlinear wire?
A.
Faraday's law
B.
Gauss's law
C.
Ohm's law
D.
Ampère's law
Ampère's law is the proper law to describe the magnetic field in a nonlinear wire, relating the circulation of the magnetic field to the electric current passing through the circuit. Hence option D is correct.
The law that describes the magnetic field in a nonlinear wire is Ampère's law. Ampère's law states that the magnetic field around an electric current is proportional to the current, with each segment of current contributing to the magnetic field. Specifically, it describes how the circulation of the magnetic field, or the line integral around a closed curve (denoted as C), is related to the electric current passing through the surface (denoted as S) that is bounded by the curve C. Importantly, the surface can be of any shape, allowing for the application of Ampère's law to wires of arbitrary configurations, including nonlinear wires.
A boy throws a water balloon at his friend. If the work done on the balloon is 20j and it has a mass of 1kg what is the speed of the balloon
Answer:
The speed of of the balloon is about 6.32 m/s
Explanation:
Assuming all of the work done is transformed into the balloon's kinetic energy, we can use the formula for the kinetic energy to answer the question:
[tex]E_k=\frac{1}{2}mv^2\\20J = \frac{1}{2}1kg\cdot v^2\implies v=\pm\sqrt{40\frac{m^2}{s^2}}\approx\pm6.32\frac{m}{s}[/tex]
Speed is the absolute value of velocity, so the speed of the balloon is about 6.32 m/s
A 1.0 kg book is at rest on a table top diagram the forces acting on the book
Answer:
In the diagram attached, we will be able to see that the total force [tex]F[/tex] acting on the book is zero, according to the First Newton law, which states that an object is in equilibrium is the total force exerted on it is zero:
[tex]F=F_{T}-W=0[/tex] (1)
Which is the same as:
[tex]F_{T}=W[/tex] (2)
Where [tex]W[/tex] is the weight of the book, which is the product of the mass [tex]m[/tex] of the book and the gravity acceleration [tex]g[/tex]:
[tex]W=mg[/tex] (3)
Being [tex]m=1.0kg[/tex] and [tex]9.8\frac{m}{s^{2}}[/tex], the weight of the book is:
[tex]W=(1.0kg)(9.8\frac{m}{s^{2}})[/tex]
[tex]W=9.8N[/tex] (4)
Then, equation (2) means that the force [tex]W[/tex] due to the weight acting on the book is the same in magnitude but in opposite direction to the force [tex]F_{T}[/tex] the table exerts on the book, which is in accordance with the third Newton law of action and reaction.
Which of the following parts of the eye is located at the back of the eye, receives focused light waves from the lens, and is composed of tiny, light-sensitive nerves? A. the retina B. the cornea C. the convex lens D. the optic nerve
That's the retina. (A)
If you think of your eye like a film camera, the retina is the film.
If you think of your eye like a digital camera, the retina is the CCD.
A person weighing 490N stands on a scale in an elevator. What does the scale read (normal force) when the elevator rises at a constant velocity of 5 m/s?
Answer:
490 N
Explanation:
The elevator is rising at constant velocity: this means the acceleration of the system is zero, so according to Newton's second law, the net force on the system is also zero:
[tex]F_{net} = ma =0[/tex]
There are two forces acting on the person standing on the scale:
- its weight, downward, whose magnitude is W=490 N
- The normal force of the scale on the person, N, which is upward
Since the net force must be zero, we have:
[tex]W-N=0[/tex]
From which we find the normal force:
[tex]N=W=490 N[/tex]
jose buys a new moped. He travels 3km south and then 4 km east. How far does he need to go to get back to where he started?
Answer: 5km by straight line, 7km by route.
Explanation:
The distance by route is 3km south and then 4km east, notice that the distances are perpendicular to each other, so the total distance traveled (by a straight line) is:
D = √((3km)^2 + (4km)^2) = √(9km^2 + 16km^2) = (√25)km = 5km
So the distance by a straight line that he needs to go back to where he started is 5km, and if he wants to get back by route, he must do 4km to the west and then 3km to the north, so a total of 7km
A Level Physics. Momentum questions.
kinematic equation used, g=10m/s/s approx
(a) 39.6 m/s and 30.7 m/s
Explanation:
Use the formula for speed as a function of distance made in a uniformly decelerated motion:
[tex]v_s^2 = v_0^2 -2sa[/tex]
with v_s the instantaneous speed at distance s and v_0 the initial speed (right after the explosion). "a" is the acceleration due to friction force, with negative sign in front of that term reflecting the fact the friction force acts against the direction of the motion. The scene after the explosion implies the fragments have come to a halt with the respective distances shown in the figure, i.e., for each fragment:
[tex]0 = v_0^2 -2sa[/tex]
and the initial speed v_0 remains to be determined:
[tex]v_0=\sqrt{2sa}[/tex]
The deceleration "a" due to friction can be found using the information we are given: the mass of a fragment and the coefficient of dynamic friction of 0.4:
[tex]F_{friction} = \mu\cdot m\cdot g \implies a = \mu\cdot g = 0.4\cdot 9.8\frac{m}{s^2}=3.92\frac{m}{s^2}[/tex]
So the initial velocities just after the explosion, as implied by the distances of 200m (v01) and 120m (v02) are, respectively:
[tex]v_{01}=\sqrt{2\cdot200m\cdot 3.92\frac{m}{s^2}}=39.6\frac{m}{s}\\v_{02}=\sqrt{2\cdot120m\cdot 3.92\frac{m}{s^2}}=30.7\frac{m}{s}[/tex]
(b) The speed of the third fragment is 31.7 m/s
Explanation:
Use the law of conservation of the momentum. At the time of the explosion there were three fragments. For two of them we have determined the initial speed in (a). Now we know that the total momentum of the system (container) right before the fragments were set into motion was 0. The total of the moment vectors (magnitudes with their directions) should still be 0 right after the explosion. Given the angle between the paths of fragment 0.5kg and 1kg, the total vector of their momentum can be calculated
[tex]\overline{p}_{12} = m_1 \overline{v}_1 +m_2\overline{v}_2\\[/tex]
and from the conservation law we know that the momentum of the third piece must be
[tex]\overline{p}_3=-\overline{p}_{12}[/tex]
in particular, its magnitude will be same as the magnitude of the resultant vector, counteracting (at an angle 180 degrees from the resultant). This will eventually allow us to determine the speed of the third fragment. The magnitudes are:
[tex] |\overline{p}_{1}| = 0.5kg\cdot 39.6 \frac{m}{s} = 19.8 kg\frac{m}{s}\\|\overline{p}_{2}|=1.0kg\cdot 30.7\frac{m}{s}=30.7kg\frac{m}{s}[/tex]
and the resulting moment:
[tex] |\overline{p}_{12}| = \sqrt{|\overline{p}_1|^2+|\overline{p}_2|^2+2|\overline{p}_1||\overline{p}_2|\cos 40^\circ}=47.6 kg\frac{m}{s}=|\overline{p}_3|[/tex]
and so the speed of the third fragment is
[tex]v_{03} = \frac{|\overline{p}_3|}{1.5kg}=\frac{47.6kg\frac{m}{s}}{1.5kg}=31.7\frac{m}{s}[/tex]
(c) The total kinetic energy is 1617 Joules
Explanation:
[tex]E_k = \frac{1}{2}\sum_{i=1}^3 m_i v_{0i}^2 = 0.5\cdot(0.5\cdot 39.6^2+1\cdot 30.7^2+1.5\cdot 31.7^2)kg\frac{m^2}{s^2}=1617.0J[/tex]
(d) The area will be proportional to the fourth power of the initial velocities.
Explanation:
Consider the area of a circle with radius equal to the distance a fragment traveled. We can choose a fragment with largest such distance or choose the average of the areas for each fragment, or another geometric measure, however, this choice won't affect the qualitative answer.
The distance of a fragment "i" traveled as a function of the initial speed is
[tex]s_i = \frac{v_{0i}^2}{2a}[/tex]
The circular area is then
[tex]A_i = \pi(\frac{v_{0i}^2}{2a})^2\implies A_i \propto v_{0i}^4[/tex]
The area due to a fragment with initial velocity is proportional to the fourth power of that velocity. This can be generalized to all fragments by assuming a common factor amplifying the velocities. Such factor will also show up in the fourth power in the area formula above, justifying the answer: the effect of an amplification of the initial speed has a fourth-power effect on the area of spread.
determine which of the following must change when pitch gets higher a.amplitude b.frequency c.wavelength d.intensity e.speed of sound waves
Higher pitch means higher frequency.
But higher frequency also means shorter wavelength, because the product of (frequency) x (wavelength) is the wave-speed, so it doesn't change.
So (b) and (c) must both change.
Answer:
Th Correct Answer is C
Explanation:
Changing Pitch
The four characteristics of the series that influence its frequency are density, diameter, tension, and length. These characteristics are illustrated below: While the length of a sequence is modified, it will reverberate with a distinct wavelength. Lower strings have a greater frequency and therefore more powerful pitch.A race car starting from rest accelerates uniformly at a rare of 4.90 meters per second^2. What is the cars speed after it has traveled 200 meters?
From the law of Galileo Galilei :v²=v₀²+2ad we take the speed
v²=0+2*4.90*200=1960=>v=√1960=44.27 m/s
Put these different types of radiation in order from MOST to LEAST penetrating.
Answer:
Alpha
These are fast moving helium atoms. They have high energy, typically in the MeV rangeDue to their large mass, they are stopped by just a few inches of air, or a piece of paper.Beta
These are fast moving electrons. They typically have energies in the range of a few hundred keV to several MeV.Gamma
These are photons, just like light, except of much higher energy,They are typically from several keV to several MeV. X-Rays and gamma rays are really the same thing, the difference is how they were produced.Answer: NO, IT'S GAMMA, BETA, THEN ALPHA
Explanation:
which color had shortest wavelength
the color violet has the shortest wavelength!
Answer: Violet! :D
Have a nice day :3
True or false: Balanced forces can change an object's direction?
The statement is false. Balanced forces can NOT change the speed OR direction of an object's motion. (See Newton's #1 law of motion.)
Answer:
False
Explanation:
As per Newton's first law of motion, an object will not change its state of motion until an external unbalanced force is applied on it.
If a balanced force is applied on an object there will be no change in state of motion. Take for example a box. One person moves it to left with force F and another person moves it to the right with same force F. The box will not move. But if the two forces are not equal then a net force will be acting on the box and it will move and its direction will be changed.
A 67kg stove is located on the 70th floor of a building (230m above ground). The stove has _______ energy. Calculate it.
Answer:
[tex]1.51\cdot 10^5 J[/tex] of gravitational potential energy
Explanation:
the gravitational potential energy of an object is given by:
[tex]U=mgh[/tex]
where
m is the mass of the object
g is the acceleration due to gravity
h is the heigth of the object above the ground
In this problem, we have:
- m = 67 kg is the mass of the stove
- g = 9.8 m/s^2 is the acceleration due to gravity
- h = 230 m is the height of the stove above the ground
Substituting into the equation, we find
[tex]U=(67 kg)(9.8 m/s^2)(230 m)=1.51\cdot 10^5 J[/tex]
Differentiate between the factor(s) that affect inertia and momentum.
Answer:
Inertia relates directly to an object's mass. It is its inherent property and expresses how much force is needed to bring the object to a certain level of acceleration. It is the sole factor.
Momentum relates proportionally to two factors: mass and velocity. As such, momentum is not an inherent property of an object but a measure dependent on it current velocity, in addition to its mass.
Answer:
Inertia relates directly to an object's mass. It is its inherent property and expresses how much force is needed to bring the object to a certain level of acceleration. It is the sole factor.
rays traveling parallel to the principle axis of a concave mirror will reflect out through the mirrors focus?
a. true
b. false
Answer:
True
Explanation:
When a ray travelling parallel to the principle axis of a concave mirror then the light ray reflect out through the mirrors and passing through the focus.
When a light ray travelling through focus of a concave mirror then after reflection the light ray reflect out through the mirror and go parallel to principle axis.
Therefore, rays travelling parallel to the principle axis of a concave mirror will reflect out through the mirrors focus.
It is true.
Answer:
true
Explanation:
What must happen to the temperature of a material for thermal expansion to occur.
Thermal expansion occurs when the temperature of a material increases, leading to greater kinetic energy and separation between atoms, causing the material to expand in all dimensions.
For thermal expansion to occur in a material, the temperature of that material must increase. This increase in temperature results in an increase in the kinetic energy of the material's atoms or molecules. As discussed in the Kinetic Theory, in a solid, this kinetic energy manifests as small, rapid vibrations which cause atoms to push neighboring atoms or molecules slightly farther apart from each other.
An increase in the average separation between particles translates into an expansion of the material in all dimensions. This behavior is observed in everyday phenomena, such as the buckling of railroad tracks due to thermal expansion. The degree to which a material expands in response to temperature change can be quantified by its coefficient of thermal expansion, which generally varies with temperature.
which of the following is not a popular surface for a tennis court?
A. wood
B. grass
C. clay
D. Hard court
The answer is A. wood
because there are three different courts: clay court, grass court, and hard court. wood isn't in there so that would be the answer.
The least popular surface for a tennis court amongst the options given is wood. This is due to its high maintenance, cost, and potential for injuries.
Explanation:In the context of tennis courts, the most commonly used surfaces are grass, clay, and hard court. These surfaces are popular due to their specific impacts on the speed, spin, and bounce of the ball, thus influencing the style of play. On the other hand, wood is not a popular or commonly used surface for a tennis court. While it is possible to play tennis on a wooden court, the maintenance and cost, coupled with the potential for injuries due to slippery surface, make it an impractical option.
Learn more about Tennis Court Surfaces here:https://brainly.com/question/4594646
#SPJ2
A centrifuge was used to separate into it’s components. What conclusions out the sample can be formed based on the technique used?
A centrifuge is used to separate specimens of different densities. It applies a centripetal force to cause the denser components to separate from the less dense ones. This technique can be used for various purposes, including cell fractionation and separating bacteria, viruses, and proteins based on their density.
Explanation:A centrifuge is a rotating device used to separate specimens of different densities. It operates by applying a centripetal force, which causes the denser components to separate from the less dense components. Based on the technique used, one can conclude that the sample was separated into its components based on differences in density.
For example, in the case of cell fractionation, a centrifuge can be used to separate subcellular structures by differences in mass. The more massive structures settle at the bottom of the centrifuge tube first, while the less massive ones remain suspended for longer. This allows for the isolation and analysis of different organelles and cellular substructures to determine their functions.
In other applications, such as in the separation of bacteria, viruses, and proteins, a centrifuge can separate these components based on their density. The heavier components settle at the bottom while the lighter ones remain suspended. This enables the isolation and study of these components individually.
Learn more about centrifuge here:https://brainly.com/question/12954017
#SPJ2
A spring with k = 500 N/m stores 704 J. How far is it extended from the equilibrium position
Given that:
k = 500 n/m,
work (W) = 704 J
spring extension (x) = ?
we know that,
Work = (1/2) k x²
704 = (1/2) × 500 × x²
x = 1.67 m
A spring stretched for 1.67 m distance.
Physic pressure chapter