Question 15 OT 25
Which process is an example of an exothermic reaction?
A. The reactions taking place in a cold pack
B. A plant using photosynthesis to create sugars
C. Natural gas burning on a stove
o
D. The reactions taking place inside a baking cake
Answer:
A. The reactions taking place in a cold pack
Explanation:
This is because in a cold pack, there is no heat gained therefore a reaction stands by losing it's own heat to the surrounding.
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2. Samuel leaves the end of a 4.0-m-high diving board and strikes the
water 1.3 s later, 3.0 m beyond the end of the board. Considering the
diver as a particle, determine:
(a) His initial velocity,
(b) The maximum height reached;
(c) The velocity Vf
with which he enters the water.
Answer:
a) v = 4.9 m/s at 62° above the horizontal
b) h = 0.94 m above the board or 4.94 m above the water
c) v = 10 m/s at 77° below the horizontal
Explanation:
Assume UP and FOREWARD are positive and the diving board is the origin.
Ignore air resistance.
s = s₀ + v₀t + ½at²
In the vertical
-4 = 0 + vy₀(1.3) + ½(-9.8)(1.3²)
vy₀ = 4.281 m/s
in the horizontal
3.0 = 0 + vx₀(1.3) + ½(0)(1.3²)
vx₀ = 2.307... m/s
v = √(4.281² + 2.307²) = 4.863...
tanθ = 4.281 / 2.307
θ = 61.680...
v² = u² + 2as
s = (v² - u²) / 2a
h = (0² - 4.281²) / 2(-9.8) = 0.9350...
v² = 4.863² + 2(9.8)(4)
v = 10.1019...
cosθ = 2.307/10.1019
θ = 76.798
(a) The initial velocity of Samuel is 4.02 m/s
(b) The maximum height reached by Samuel is 0.55 m
(c) The final velocity when he enters the water is 5.20 m/s
The given parameter:
the height of the board, h = 4 mtime to strike the water, t = 1.3 sthe horizontal distance traveled, x = 3.0 m(a) The initial velocity of Samuel is calculated as;
[tex]h = v_o_y t + \frac{1}{2} gt^2\\\\[/tex]
Assume downward motion to be in negative direction
The vertical component of the velocity is calculated as;
[tex]4 = 1.3\times v_0_y + 0.5\times 9.8\times 1.3^2\\\\4 = 1.3v_{0y} + 8.281\\\\1.3v_{0y} = 4- 8.281\\\\1.3v_{0y} = -4.281\\\\v_{0y} = \frac{-4.281}{1.3} \\\\v_{0y} = -3.293 \ m/s\\\\v_{0y} = 3.293 \ m/s \ \ \ (downwards)[/tex]
The horizontal component of the velocity is calculated as;
Assume forward motion to be in positive direction
[tex]x = v_{0x}t \\\\3 = 1.3v_{0x}\\\\v_{0x} = \frac{3}{1.3} \\\\v_{0x} = 2.308 \ m/s[/tex]
The resultant of initial velocity is calculated as;
[tex]v_0 = \sqrt{v_{0y}^2 + v_{0x}^2} \\\\v_0 = \sqrt{3.293^2 + 2.308^2} \\\\v_0 = \sqrt{16.17} \\\\v_0 = 4.02 \ m/s[/tex]
(b) The maximum height reached by Samuel is calculated as;
[tex]v_f_y^2 = v_0_y^2 + 2gh\\\\at \ maximum \ height \ v_{fy} = 0\\\\0 = v_0_y^2 + 2gh\\\\-2gh = v_0_y^2\\\\h = \frac{v_0_y^2}{-2g} \\\\h = \frac{(3.293)^2}{-2\times 9.8} \\\\h = -0.55 \ m\\\\h = 0.55 \ m \ (downwards)[/tex]
(c) The final velocity when he enters the water;
The height traveled before he hits the water, h = 0.55 m
[tex]v_f^2 = v_{0}^2 + 2gh\\\\v_f^2 = (4.02)^2 + (2\times 9.8\times 0.55)\\\\v_f^2 = 26.94\\\\v_f = \sqrt{26.94} \\\\v_f = 5.20 \ m/s[/tex]
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60.96-mile distance in kilometers
Answer:
98.105610 Kilometers
Explanation:
Rounded to 8 digits
Answer:
98.11 km
Explanation:
60.96 mi (5280ft/mi)(12 in/ft)(2.54 cm/in)(1 m/ 100cm)(1 km/1000 m) = 98.10561024 km
however, reporting this precision to the nearest hundred millionth of a kilometer is silly as we only know the mile dimension to the nearest hundredth of a mile.
A hundredth of a mile is 5280/100 = 52.8 ft or just over 16 m
It would only be a little bit of a presumption to give our precision to the nearest 10 meters as I have done.
This also fits neatly into the significant digits rule. Both the original dimension and the converted dimension have four significant digits.
which form of the energy is used to generate electrical energy in a tidal power station
Tidal energy is the form of energy used to generate electrical energy.
The form of the energy is used to generate electrical energy in a tidal power station is kinetic energy.
What is kinetic energy?Kinetic energy is the energy that an object has as a result of its movement. If we intend to accelerate an object, we should indeed apply force to it. Using force requires us to put in effort.
After work is completed, energy is transmitted to the object, and the object moves at a new constant speed.
Tidal energy is generated by the movement of our tides and oceans, where the intensity of the water from tide rise and fall is a type of kinetic energy.
Tidal power is related to gravitational hydropower, which uses water movement to propel a turbine and generate electricity.
Thus, kinetic energy is used to generate electrical energy in a tidal power station.
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What is the difference between a scientific theory and a scientific law
Scientific laws are summaries or statements that describe a wide range of observations and results of experiments.
Scientific theories, on the other hand, are explanations for observations and results.
So, laws describe what happens and theories explain why things happen.
hope this help! ^^
What is the velocity of a car that traveled a total of 75 kilometers north in 1.5 hours?
What are you solving for?
What’s the equation?
Show work!
Help pleaseee!
Answer:
50km/hr is the velocity of a car that traveled a total of 75 km North in 1.5 hours.
.
An object accelerates from 10 m/s to 30 m/s in 4.0 seconds.
The accelerating force is 150 N.
What is the mass of the object?
Answer:
m=30kg
Explanation:
m=[tex]\frac{F}{a}[/tex] ............(1)
F=150N
a=?
a=[tex]\frac{vf-vi}{t}[/tex]
a=[tex]\frac{30-10}{4}[/tex]
a=[tex]\frac{20}{4}[/tex]
a=5ms^-2
Putting the value of "F" and "a" in eq (1),
m=[tex]\frac{150}{5}[/tex]
m=30kgThe scatter plot shows the number of minutes Guya practiced the flute each day in a given week.
How many minutes did Guya practice on Tuesday?
A) 1min
B) 2min
C) 20min
D) 30 min
If the scatter plot shows the number of minutes Guya practiced the flute each day in a given week, then Guya practiced 20 minutes on Tuesday, therefore the correct answer is option C.
What is a scatter plot?A set of dots plotted on a horizontal and vertical axis is known as a scatter plot. Because they may demonstrate the degree of connection, if any, between the values of observed quantities or events, scatter plots are crucial in statistics.
As given in the problem If the scatter plot shows the number of minutes Guya practiced the flute each day in a given week,
The x coordinates is showing the days of practice and the y coordinate is showing the number of minutes he practiced the flute on a given day,
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A mineral oil has a density of 0.875 g/cm3. Suppose you spread 0.60 g of this oil over the surface of water in a large dish with an inner diameter of 21.6 cm. How thick is the oil layer
With a density of 0.875 g/cm³, a sample of 0.60 g of this oil would have a volume V such that
0.875 g/cm³ = (0.60 g)/V ==> V ≈ 0.686 cm³
If the oil is spread out uniformly over the water's surface, then it forms a cylinder whose diameter is equal to that of the dish, 21.6 cm. Then the thickness d of the oil cylinder is such that
V = π ((21.6 cm)/2)² d ==> d ≈ 0.0202 cm
Which Scientist discovered
atomic Theory?
Answer:
John dalton discovered
Un telescopio indica que la posición de un satélite de comunicaciones está determinada por el punto P (7x105m, 5x105m) . ¿A qué distancia se encuentra el satélite del telescopio? En que dirección viajará una señal que sale del telescopio hacia el satélite?
a) La Distancia entre el telescopio y el satélite es aproximadamente [tex]8.602\times 10^{5}[/tex] metros.
b) La señal sale del telescopio y se desplaza [tex]7\times 10^{5}[/tex] metros en Dirección + x y [tex]5\times 10^{5}[/tex] metros en Dirección +y.
a) Si asumimos la Posición del telescopio como el Origen de un Marco de Referencia, entonces la Distancia entre el telescopio y el satélite ([tex]d[/tex]), en metros, mediante la siguiente expresión:
[tex]d = \sqrt{(S(x,y) - O(x,y))\,\bullet\,(S(x,y) - O(x,y))}[/tex] (1)
Donde:
[tex]S(x,y)[/tex] - Coordenadas del satélite, en metros.[tex]O(x,y)[/tex] - Coordenadas del telescopio, en metros.Si sabemos que [tex]O(x,y) = (0, 0)[/tex] y [tex]S(x,y) = (7\times 10^{5}, 5\times 10^{5})[/tex], entonces la Distancia entre el telescopio y el satélite es:
[tex]d = \sqrt{(7\times 10^{5})^{2}+(5\times 10^{5})^{2}}[/tex]
[tex]d \approx 8.602\times 10^{5}\,m[/tex]
Nota - (1) es una forma vectorial del Teorema de Pitágoras.
La Distancia entre el telescopio y el satélite es aproximadamente [tex]8.602\times 10^{5}[/tex] metros.
b) La señal sale del telescopio y se desplaza [tex]7\times 10^{5}[/tex] metros en Dirección + x y [tex]5\times 10^{5}[/tex] metros en Dirección +y.
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An astronaut on a strange planet finds that she can jump a maximum horizontal distance of 15m if her initial speed is 3m/s.What is the acceleration due to gravity on the planet?
Explanation:
As the astronaut jumps and reaches the highest point, he is momentarily at rest, i.e.
[tex]v=0[/tex]
We also know
[tex]u=3, s=15[/tex]
By the formula,
[tex]v^2-u^2=2as[/tex]
where a is the acceleration of objectc due to gravity,
[tex]0^2-3^2=2a(15)[/tex]
[tex]-9=30a[/tex]
[tex]a=-0.3 ms^{-2}[/tex]
where negative sign indicates a downwards acceleration.
Three resistors 2 k\ohm, 2.5 k\ohm and 3 k\ohm are connected in series. A power supply is connected in the circuit, and applies a voltage of 10.00 V across all three. Calculate the current in the circuit. Enter results in terms of milliamps (mA).
Answer:
1.33 mA
Explanation:
V=IR
I=10/(7.5×10³)
=1.33×10-³A
=1.33mA
A black ball moving to the left at 3 m/s collides with a white ball at rest. Which direction will the balls move after the collision?
Answer: the location from where the black ball was thrown from because after the collision the velocity will make it still go further not stop
Explanation:
How would you determine the sign of a charge on a body using an electroscope? PLEASE HELP!!!
Answer:
Now the electroscope will allow you to identify whether an object is positively or negatively charged. If you bring a negative object near the electroscope, the electrons in the scope will be repelled toward the leaves, balancing the charge.
Explanation:
The electrostatic force obeys the principle of linear super-position which basically states
that force between two particles does not get affected by the charge of the other and hence if the
rod is brought close to a suspended metal needle and is getting attracted then needle definitely
should possess opposite charge relative to the rod or basically negative charge as opposite charges
attract.
(b) In case the needle which is brought near the sus[ended needle and gets repelled that shows that
both of them possess same charge and hence positive charge on both objects and will start
repelling each other.
HELP PLEASE ASAP!!!
I CAN'T FAIL PHYSICS
xoxo thank you!
Forces is F1(east) and F2 are simultaneously applied to
a 30kg mass. When f2is east , a = 5.0 m/s2 east and
When F2 is west a=10m/s² east - Determine the
Magnitude of f1 and f2
There's a problem with the given information, but I'll get to that later.
Use Newton's second law. When F₂ points east, we have
F₁ + F₂ = (30 kg) (5.0 m/s²) = 150 N
and when F₂ points west, it acts in the opposite direction and
F₁ - F₂ = (30 kg) (10 m/s²) = 300 N
Solve for F₁ and F₂ : we have
(F₁ + F₂) + (F₁ - F₂) = 150 N + 300 N
2F₁ = 450 N
F₁ = 225 N
and
(F₁ + F₂) - (F₁ - F₂) = 150 N - 300 N
2F₂ = -150 N
F₂ = -75 N
But F₁ and F₂ are magnitudes, so they must be positive! Also, it doesn't make sense that when the forces both point east, the mass accelerates less than it does when the forces work against each other. Probably one of the given accelerations are supposed to point west instead of east.
What is the relationship between resistivity of a wire and length of a wire is?
[tex]\boxed{\sf R=\rho\dfrac{\ell}{A}}[/tex]
Or
[tex]\\ \rm\hookrightarrow \rho=R\dfrac{A}{l}[/tex]
Rho stands for resistivity of wireR stands for resistance of wire l stands for length of areaA stands for surface area of wireWhat is the density of a block of marble that
occupies 287 cm3
and has a mass of 816 g?
Answer in units of g/cm3
.
Explanation:
Solution,
Volume (v)=287 cm^3
Mass(m)=816 g
Density(d)=m/v
=816/287
=2.84
So, the density of the block of marbles is 2.84 g/cm^3.
I hope it helped U
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An arrow is moving at 35 m/s and travels for 5 seconds. How far did the arrow travel?
What are you solving for? Show work! Help please!
Answer:
175m
Explanation:
So it’s travelling at 35metres/1second so if we want to find 5 seconds we can do this…
[tex]\frac{35}{1} \frac{x}{5}.... so[/tex] 35x5 ÷ 1 = 175m/5 seconds
Answer:
175 is the right answer 35×5=175
Explanation:
175
Physics help please !!!
Answer:
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A scientist obtains images of a particular star, which appears as four separate stars.
Which phenomenon causes the star to appear this way?
O redshift
gravitational lensing
O principle of equivalence
O gravitational time dilation
Answer:
gravitational lensing
Explanation:
Answer:
Gravitational lensing
Explanation:
PLEASE HELP REALLY WOULD APPRECIATE THE HELP;) A positively charged glass rod is bought close to a suspended metal needle. What
can we say about the charge on the needle given that the needle is
a) attracted ?
b) repelled ?
Answer:
Explanation:
attracted
Yellow light passes through a diffraction grating. it's first order maximum occurs at an angle of 21.2. What is the slit separation d?
Answer:
19.284
or
9.33
Explanation:
Answer:
1.66
Explanation:
Found answer on chegg. Works for acellus
Question 3 of 10
According to the law of conservation of energy, which statement must be
true?
A. A system cannot take in additional energy.
B. Potential energy can only change to kinetic energy.
O C. There is only one form of energy.
D. The total energy of a system can decrease only if energy leaves
the system
Answer:
b
Explanation:
the law says that energy can not be created or destroy but can be transform from one energy to another.
A uniform rod of length 0.7 m and mass 10 kg rotates freely about a horizontal axis passing through one end of the rod a bullet of mass 20 g traveling horizontally with velocity v=200 m/s penetrates the end of the rod. and hooked on the rod find the angular velocity of the rod when the bullet hits the bar
Answer:
ω = 1.7 rad/s
Explanation:
Conservation of angular momentum
Assuming the rod is initially hanging vertically at rest.
Initial angular momentum is carried by the bullet only
L = Iω = (mR²)(v/R) = mvR = 0.020(200)(0.7) = 2.8 kg•m²/s
the same angular momentum exists after impact, only the moment of inertia has increased by that of the rod. I = ⅓mR²
2.8 = (⅓(10)(0.7²) + 0.020(0.7²))ω
2.8 = (1.64313333...)ω
ω = 1.70406134...
25m/s to miles/hr step by step
What is the speed of a car that traveled 32 m in 2 seconds?
Write the following as full (decimal) numbers with standard units metric (SI) units:
(For example, 80.2 kA = 80,200 A)
651.9 mm
71 V
910 mg
30.0 ps
22.5 fm
2.00 gigavolts
Answer:
Explanation:
651.9 mm = 0.6519 m
71 V = 71 V
910 mg = 0.000910 kg
30.0 ps = 0.000 000 000 030 0 s
22.5 fm = 0.000 000 000 000 022 5 m
2.00 gigavolts = 2 000 000 000 V
16. A horizontal pipe with a cross-section of 10 cm?which is joined to another horizontal pipe of 50 cm Cross-sectional area. The speed of water in the small pipe is 6 m/s and the pressure there is 200 kPa. The pressure in the large pipe, in Pa. is
A. 183
B. 217000
C. 217
D. 235000
Answer:
b
Explanation: