1. Since the body is thrown vertically upward, the only force acting on it as it rises and falls is gravity, which causes a constant downward acceleration with magnitude g = 9.8 m/s². Because this acceleration is constant, we can use the formula
v² - u² = 2a ∆x
where
u = initial speed
v = final speed
a = acceleration
∆x = displacement
At its maximum height, some distance y above the point where the body is launched, the body has zero velocity, so
0² - (20 m/s)² = 2 (-9.8 m/s²) y
Solve for y :
y = (20 m/s)² / (2 (9.8 m/s²)) ≈ 20.4 m
2. Relative to the ground, the body's maximum height is 60 m + 20.4 m ≈ 80.4 m.
3. At any time t ≥ 0, the body's vertical velocity is given by
v = 20 m/s - gt
At the highest point, we have
0 = 20 m/s - (9.8 m/s²) t
and solving for t gives
t = (20 m/s) / (9.8 m/s²) ≈ 2.04 s
4. The body's height y above the ground at any time t ≥ 0 is given by
y = 60 m + (20 m/s) t - 1/2 gt²
Solve for t when y = 0 :
0 = 60 m + (20 m/s) t - 1/2 (9.8 m/s²) t²
Using the quadratic formula,
t = (-b + √(b² - 4ac)) / (2a)
(and omitting the negative root, which gives a negative solution) where a = -1/2 (9.8 m/s²), b = 20 m/s, and c = 60 m. You should end up with
t ≈ 6.09 s
5. At the time found in (4), the body's velocity is
v = 20 m/s - g (6.09 s) ≈ -39.7 m/s
Speed is the magnitude of velocity, so the speed in question is 39.7 m/s.
Waves can be refracted.
Explain this term.
HELP PLSSS
Answer: By "waves can be refracted" they mean that refraction can occur with waves. To better explain, refraction is the "change in direction of a wave passing from one medium to another or from a gradual change in the medium." You probably know this best when you put a pencil inside a glass of water where the pencil bends a bit. The same can happen with sound or water waves as well!
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Help me quickly! please!!!
A cable pulls a car up a mountain with a force of 4 × 103 N at a vertical constant velocity of 5 m.s-1. It takes 5 minutes to reach the top.
(a)How much work is done in getting the car to the top?
(b)How much work would have been done if the vertical speed was 2,5 m.s-1?
(c)Calculate the power exerted on the cable car in those 5 minutes.
Answer:
(a) 6,000,000J
(b) 3,000,000J
(c) For A 20,000W
But for B 10,000W
The work done in getting the car to the top is equal to 6 ×10⁶ J. If the vertical speed is 2.5 m/s then, the work done will be 3 ×10⁶ J. The power exerted on the car is in 5 minutes is 20000 J/s.
What is work done ?In physics, work done is the dot product of force and displacement. Let w be the work done and F and ds be the force and displacement. Then
W = F.ds
It is given that the, the force of the cable is 4 × 10³ N. The velocity is 5 m/s and time is 5 minutes or 300 seconds. Now, the displacement is the product of time and velocity.
ds = velocity × time
= 300 s × 5 m/s
= 1500 m.
Thus the work done = F × ds
= 4 × 10³ N × 1500 m
= 6 ×10⁶ J .
If the velocity is reduced to half 2.5 m/s , then work done will be reduced to half as 3 ×10⁶ J.
Power is the rate of work done. Thus it is the ratio of work done to time. The power exerted on the car in 5 minutes = 6 ×10⁶ J /300s
= 20000 J/s
Hence, the power exerted on the cable car in 5 minutes is 20000 J/s.
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Imagine that a car is speeding down the highway and it hits a large bump in the road that forces it off the road. What would Newton call that object?
A.
a physical object
B.
a course interrupter
C.
an unbalanced force
D.
an unfortunate event
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Answer:
C. unbalanced force
Explanation:
it is called unbalanced force because it has changed direction of the moving object
25 n object requires a 5. 0 n to start moving over a horizontal surface. What is the coefficient of static friction?.
Answer:
μ=1/5=0.2
Explanation:
using the formula
Fs=Fn*μ
Where
Fs is the static force
Fn = Normal force
μ= coefficient
so if Fn=25n
and it requires 5 n to start moving, means the max Fs is 5n
5=25μ
μ=5/25
μ=1/5=0.2
Please give an answer that is coherent
A ceiling fan operates at three speeds, using 120 V of electricity from the wall. At low speeds, it uses 0.25 A. Calculate the resistance needed to generate that current. Then in 1-2 sentences, describe how the resistance would change at medium and high speeds if larger currents are needed at those speeds. Your answer should include the calculated resistance and a sentence describing your reasoning.
Answer:
480
Explanation:
resistance equals to potential difference divide by electric current
120÷0.25
=480
Answer:
[tex]\mathsf {480 \Omega}[/tex]
Explanation:
[tex]\textsf {Formula used for calculating resistance :}[/tex]
[tex]\mathsf {Resistance = \frac{Voltage}{Current} }[/tex]
[tex]\textsf {This is otherwise known as Ohm's Law, hence the unit of resistance.}\\[/tex]
[tex]\textsf {Solving :}[/tex]
[tex]\implies \mathsf {R = \frac{120}{0.25}}[/tex]
[tex]\implies \mathsf {R = 480\Omega}[/tex]
[tex]\textsf{If the fan uses higher current at higher speeds, then}\\\textsf{the resistance would decrease as it is inversely}\\\textsf {proportional to the current.}[/tex]
Which of the following will require most developed countries to
decrease emissions of carbon dioxide and other greenhouse gases?
a. Montreal Protocol c. Emissions Reduction Act
b. Kyoto Protocol d. Reforestation Project
Answer:
Kyoto Protocol
Explanation:
Which of the following is NOT an indicator of a chemical reaction?
OPTIONS
A. A phase change
B. A temperature change
C. A color change
D. A gas being created
Answer:
c
Explanation:
The changing of color of a substance is not necessarily an indicator of a chemical change. For example, changing the color of a metal does not change its physical properties. However, in a chemical reaction, a color change is usually an indicator that a reaction is occurring.
A state government wants to increase the taxes on cigarettes to increase tax revenue. Because cigarettes are addictive, we would expect its demand to be: ______________
a. Elastic, Thus, the government's cigarette-tax revenues would rise with a tax increase.
b. Elastic, Thus, the government's cigarette-tax revenues would fall with a tax increase.
c. Inelastic, Thus, the government's cigarette-tax revenues would rise with a tax increase.
d. Inelastic, Thus, the government's cigarette-tax revenues would fall with a tax increase.
The demand of cigarette is elastic so the government's cigarette-tax revenues would rise with a tax increase.
The demand of cigarette is elastic because of the addiction the people can buy the cigarette even at high prices and the government's cigarette-tax revenues would rise.
The demand for cigarettes is unitary elastic (−1.06) means that a 1% increase in the price of cigarette would reduce its consumption by 1.06% so we can conclude that the demand of the cigarette is elastic and the government revenues increases.
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what kind of frog species is this
Answer: i think its a bullfrog forgive me if im wrong i dont exactly know
Explanation:
Answer:
that is an African bullfrog
Công thức cộng vận tốc
Answer:
you are very kind except for your habit
An ice skater at rest on ice catches a dance partner moving 1.5 m/s during a performance. The ice skater has a mass of 75 kg and the dance partner has a mass of 50 kg. What is the speed of the ice skater and dance partner after the collision?
which jovian planet should have the most extreme seasonal changes?
Answer:
Uranus
Explanation:
brainliest please?
the primary factor in decreasing the kinetic energy of an object is to
Answer:
Decreasing the velocity
Explanation:
The primary factor in decreasing the kinetic energy of an object is to decrease the velocity of the object.
What is Kinetic energy?The kinetic energy of an object is the energy which it possesses due to the motion of the object. Kinetic energy is defined as the work which is needed to accelerate an object of a given mass from the state of rest to its stated velocity and direction. Gain of the energy during the acceleration of an object, the body maintains this kinetic energy unless its speed changes and the object accelerates.
The kinetic energy is directly proportional to the mass and the velocity of the object. The primary factor which is responsible for the decrease in the kinetic energy of an object is to decrease the velocity of the object.
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I need help in question 7, a and b.
Answer:
The graph for 7a is shown in the attachment. For question 7b she walks a distance of 16 meters. (m)
Explanation:
What is a milliliter.
A milliliter, abbreviated as ml or mL, is a unit of volume in the metric system. One milliliter is equal to one thousandth of a liter, or 1 cubic centimeter. In the imperial system, that's a small amount: . 004 of a cup
What would be the extension of the spring for a 3 N weight if the extension of the spring was 4 mm for a 50 g mass?
А 4 mm B)8 mm C)12mm D)24 mm
Answer:
24mm
Explanation:
3 N to g is 305.9 g
50g ---- 4 mm
305.9 ----- 4×305.9/50 = 24 mm
sports photographers often use large aperture, long focal length lenses. what limitations do these lenses impose on the photographs?
Answer:
The depth of focus achievable with those lenses is small.
Explanation:
A larger aperture makes it much harder to focus on more than one object. When using a telephoto lens (the ones the question is referring to), the depth of focus is very small. For example, using a telephoto lens to take a photo of a runner might get the runner in focus, but certainly not the track, or the audience behind them. If you look at photos, especially older photos, of Olympians in almost any sport you can see this.
Hope this helps!
When is there no atmospheric pressure pjysics.
A 50-kg girl lifts a 1-kg box vertically upward a distance of 0.5 meter. How
much work is done on the box?
Answer:
Given mass = 2kg, height = 10m,g = 9.8.
We know that Work done W = FD
= > W = (mg)(D)
= > W = (2 * 9.8)(10)
= > W = 196 Joules.
Explanation:
Yan :).
A copper (Young's modulus 1.1 x 1011 N/m2) cylinder and a brass (Young's modulus 9.0 x 1010 N/m2) cylinder are stacked end to end, as in the drawing. Each cylinder has a radius of 0.24 cm. A compressive force of F = 7900 N is applied to the right end of the brass cylinder. Find the amount by which the length of the stack decreases.
We have that for the Question, it can be said that the amount by which the length of the stack decreases is
[tex]dl'=3.621*10^{-4}m[/tex]
From the question we are told
A copper (Young's modulus 1.1 x 1011 N/m2) cylinder and a brass (Young's modulus 9.0 x 1010 N/m2) cylinder are stacked end to end, as in the drawing. Each cylinder has a radius of 0.24 cm.
A compressive force of F = 7900 N is applied to the right end of the brass cylinder. Find the amount by which the length of the stack decreases.
Generally the equation for copper cylinder is mathematically given as
[tex]dl=\frac{Flo}{yA}[/tex]
[tex]dl=\frac{7900*3*10^-^2}{1.1*10^{11}*\pi(0.24*10^{-2})^2}[/tex]
[tex]dl=1.19064778*10^-^4[/tex]
Generally the equation for brass cylinder is mathematically given as
[tex]dl=\frac{7900*5*10^-^2}{9*10^{10}*\pi(0.24*10^{-2})^2}[/tex]
[tex]dl=2.43*10^{-4}[/tex]
Therefore Total change in length
[tex]dl'=1.191*10^-^4+(2.43*10^{-4})[/tex]
[tex]dl'=3.621*10^{-4}m[/tex]
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easy one - giving brainly if correct.
Gas.
HOPE YOU GET 100!
How many sulfur atoms are there in 25 molecules c4h4s2?.
Change.
Wax melting is an example of a chemical reaction.
True or false
Please I need help fast <3
Answer:
Where is the picture send again please
Explanation:
The range of a target is found to be 20km. A shell leaves a gun with a velocity of 500m/s . What must be the angle of elevation of the gun if the ground is level
The angle of elevation of the shell must be approximately 25.840° in order to have a reach of 20 kilometers.
The shell experiments a parabolic motion, which is a combination of horizontal uniform motion and vertical uniform accelerated motion. If initial height of the shell is the same that its final height, then the range of the shell ([tex]d[/tex]), in meters, is described by the following expression:
[tex]d = \frac{v^{2}}{g}\cdot \sin 2\theta[/tex] (1)
Where:
[tex]v[/tex] - Initial speed of the shell, in meters per second[tex]g[/tex] - Gravitational acceleration, in meters per square second[tex]\theta[/tex] - Angle of elevation, in sexagesimal degreesIf we know that [tex]v = 500\,\frac{m}{s}[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex] and [tex]d = 20000\,m[/tex], then the angle of elevation is:
[tex]\sin 2\theta = \frac{d\cdot g}{v^{2}}[/tex]
[tex]\theta = \frac{1}{2}\cdot \sin^{-1} \frac{d\cdot g}{v^{2}}[/tex]
[tex]\theta = \frac{1}{2}\cdot \sin^{-1} \frac{(20000\,m)\cdot \left(9.807\,\frac{m}{s^{2}} \right)}{\left(500\,\frac{m}{s} \right)^{2}}[/tex]
[tex]\theta \approx 25.840^{\circ}[/tex]
The angle of elevation of the shell must be approximately 25.840° in order to have a reach of 20 kilometers.
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How many molecules of Oxygen gas are there on the reactant side of this equation?
C2H6 + 402 ———-> CO2 + H2O
O2
O3
04
O8
Answer:
4
Explanation:
It has 8 O atoms and 4 O2(g) molecules
I need help quickly pls
Answer:
Ok I'm not 100% on this one but, try 3 lifes sorry if u get it wrong D:
Explanation:
What type of watches are used nowadays to measure time? Explain one of
them?
Answer:
Furthermore, some modern watches (like smart watches) even incorporate calculators, GPS and Bluetooth technology or have heart-rate monitoring capabilities, and some of them use radio clock technology to regularly correct the time. Most watches that are used mainly for timekeeping have quartz movements.
Explanation:
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Walter has a paper due on a novel that he has not read. He knows that his teacher will expect detailed references to the novel in his paper. He is thinking that he can listen to it while he is lifting weights and multi-task. What is the BEST response to Walter?
A.
He does not really need to concentrate on exercise, so it is fine.
B.
He would be better off focusing on his workout and then turning to the novel.
C.
If he is doing a type of exercise that allows him to stop and take notes, it is fine.
D.
Doing as many tasks as possible is generally a good idea and promotes efficiency.
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Answer:
I'm no expert, but multitasking is a no bueno. Because multitasking reduces your efficiency and performance because your brain can only focus on one thing at a time. When you try to do two things at once, your brain lacks the capacity to perform both tasks successfully.
Therefore I would choose A, considering he could easily workout another time, whilst the test is a one time thing. He can't redo the test, but he can workout again. So my answer is A.
If he HAS to workout and study at the same time, then C would be appropriate.
I hope this helps!
what third force must be added to the two forces 30 Newton at 30 degree and 80 Newton at 135 degree the resolution for equal to zero
Answer:
Resolve the vectors:
F1 = 30 cos 30 i + 30 sin 30 j = 26 i + 15 j
F2 = 80 cos 135 i + 80 sin 135 j = -56.6 i + 56,6 j
F1 + F2 = (26 - 56.6) i + (15 + 56.6) j = -30.6 i + 71.6 j
The offsetting force would be
F3 = 30.6 i - 71.6 j
The magnitude of this vector is (30.6^2 + 71.6^2)^1/2 = 77.9
cos theta 3 = 30.6 / 77.9 = 66.9 deg
Check:
77.9 * sin 66.9 = 71.6 agreeing in magnitude with F3
Now we need the quadrant of the offsetting vector
sin theta 3 = - cos theta 3 = +
This occurs in the fourth quadrant and theta 3 = 360 - 66.9 = 293.1 deg