Answer:
B
Explanation:
Simply take all forces pointing to the right of the box as positive and all of the forces pointing to the left of the box as negative and add all values.
ΣF = 7 + 18 + (-20) = 5N to the right
A boy weighing 445 N swings on a 2-m long swing. If his horizontal speed at the lowest point is 3 m/s, what total force must the ropes holding the swing be able to withstand?
Explanation:
We need to calculate the centripetal force:
Fc = W + F
With Fc being the centripetal force, W the weight of the boy, F the centrifugal force (apparent).
We know that we can calculate the apparent centrifugal force thank to the formula:
F = (m·v²)/r = 204N
So we can write:
Fc = W + F = 445N + 204N = 649N
Which is better, forward bias or reverse bias, and why ?!
Answer:
reverse bias
Explanation:
bcz the potential barrier and impedes the flow of charge carriers. In contrast, a forward bias weakens the potential barrier, thus allowing current to flow more easily across the junction.
A 1250 kg car is stopped at a traffic light. A 3550 kg truck moving at 8.33 m/s strikes the car from behind, causing the bumpers to lock together.
A) What is the momentum of the car-truck system before the collision?
B) What is the momentum of the car-truck system after the collision?
C) How fast do the car and truck move after the collision?
(Do NOT put any links or reproductions, I just need help with this.)
A) Before the collision, the total momentum is
(1250 kg) (0 m/s) + (3550 kg) (8.33 m/s) ≈ 29,600 kg•m/s
B) Momentum is conserved, so after the collision it is still approximately 29,600 kg•m/s.
C) If v is the speed of the locked car-truck system, then
(1250 kg) (0 m/s) + (3550 kg) (8.33 m/s) = (1250 kg + 3550 kg) v
Solve for v :
29,571.5 kg•m/s = (4800 kg) v
v ≈ 6.16 m/s
An astronaut uses a pendulum with a mass of 0.200 kg to measure the acceleration due to gravity on Planet X. He lifts the pendulum's mass a vertical height of 0.500 m and is able to determine that it gains 15.0 J of gravitational potential energy as it is lifted. Using this information, calculate the acceleration due to gravity (g) on Planet X
Answer:
Explanation:
PE = mgh
g = PE/mh
g = 15.0 / (0.200(0.500))
g = 150 m/s²
This is one strong astronaut if he can work in an environment where gravity is more than 15 times stronger than on earth.
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In introductory physics, a typical cavendish balance for measuring the gravitational constant G use metal masses 2.39kg and 16g whose center are separated by 6.81cm calculate the gravitation force between these forces, treating each as a point mass located at the center of the sphere.
gravitational constant =6.67259 × 10⁻¹¹N·m²/kg²
Answer:
Explanation:
F = GMm/d²
F = 6.67259 x 10⁻¹¹(2.39)(0.016) / 0.0681²
F = 5.5019685...x 10⁻¹⁰ N
round as appropriate, probably no more than 3 significant figures.
Value of G seems low, but well within the 3 significant figures of the other numerals. I typically see G = 6.674 x 10⁻¹¹
refers to a fear of being trapped in a crowded, public place.
Answer:
Agrophobia
Explanation:
an anxiety disorder in which someone feals anxious and scared in a public place
a bicycle with tires 68 cm in diameter travels 9.2 km. how many revolutions do the wheels make
Answer:
Explanation:
Circumference in meters is
C = πD = 0.68π
9200 m / 0.68π m = 4,306.545518...
4,306.5 revolutions
A bicycle with tires 68 cm in diameter travels 9.2 km. the number of revolutions made by the wheel would be 4309
What is Velocity?The total displacement covered by any object per unit of time is known as velocity. It depends on the magnitude as well as the direction of the moving object. It can also be represented by the infinitesimal rate of change of displacement with respect to time. The unit of velocity is meter/second.
The mathematical expression for velocity is given by
velocity= displacement / time taken
As given in the problem a bicycle with tires 68 cm in diameter travels 9.2 km
Diameter = 68 cm
radius = diameter /2
= 68/2
= 34 cm
The distance covered by the tire in one cycle would be
distance in one revolution = 2π×Radius
= 2×3.14× 34
= 213.52 cm
=2.13 m
The number of revolutions by wheel = total distance/distance in one revolution
number of revolutions = 9200/2.135
=4309 revolutions
Thus, the number of revolutions made by the wheel would be 4309
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A. In the Bohr model of the hydrogen atom, the speed of the electron is approximately
2.16 × 10⁶ m/s. Find the central force acting on the electron as it revolves in a circular orbit of radius 5.17 × 10⁻¹¹ m.
Answer in units of N.
B. Find the centripetal acceleration of the electron
Explanation:
A. The centripetal force experienced by an electron as it goes around a hydrogen nucleus is given by
[tex]F_c = m_e\dfrac{v^2}{r}[/tex]
where [tex]m_e = \text{electron\:mass} = 9.11×10^{-31}\:\text{kg}[/tex]
[tex]r = 5.17×10^{-11}\:\text{m}[/tex] = orbital radius
[tex]v = 2.16×10^6\;\text{m/s}[/tex] = orbital velocity
so the centripetal force is
[tex]F_c = (9.11×10^{-31}\:\text{kg})\dfrac{(2.16×10^6\;\text{m/s})^2}{5.17×10^{-11}\:\text{m}}[/tex]
[tex]\;\;\;=8.22×10^{-8}\:\text{N}[/tex]
B. The electron's centripetal acceleration is given by
[tex]a_c = \dfrac{v^2}{r}[/tex]
Using the values from (A), we get
[tex]a_c = \dfrac{(2.16×10^6\;\text{m/s})^2}{5.17×10^{-11}\:\text{m}}[/tex]
[tex]\;\;\;=9.02×10^{22}\:\text{m/s}^2[/tex]
A metal bar has a volume of 32 cm3. The mass of the bar is 256 g. What is the density of the metal? A. 290 g/cm3 6 B. 8,200 g/cm C. 8.0 g/cm3 O D. 220 g/cm
The density of the metal is ρ = 8.0g/cm³.
Why is density important?The measure of material how densely it is packed together is called density. As the mass per unit volume, it has that definition. Symbol for density: D or Formula for Density: When is the density, m is the object's mass, and V is its volume, the equation is: = m/V.
Because it enables us to predict which compounds will float and which will sink in a liquid, density is a crucial notion. As long as an object's density is lower than the liquid's density, it will often float.
Equation :To the given equation we have :
mass of the bar = 256g
volume of metal bar = 32cm³
So according to the formula of density
ρ = m/V
So, putting values
ρ = 256g /32cm³
ρ = 8.0g/cm³
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12- Calculate the power when a force of 60N moves an object over a distance of 0.6 km in 20
minutes
A. 100watts
B. 6,000 watts
C. 0.25watts
D. 30 watts
Hi there!
To solve, we must begin by calculating the total WORK done on the object.
W = F · d (Force · displacement)
Plug in the given values. Remember to convert km to m:
1 km = 1000 m
0.6 km = 600 m
W = 60 · 600 = 36000 J
Now, we can solve for power:
P = W/t
Convert minutes to seconds:
1 min = 60 sec
20 min = 1200 sec
P = 36000/1200 = 30 W ⇒ Choice D.
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Describe what happens when iron and oxygen combine. Can the change be reversed?
Answer:
iron combines with oxygen to produce rust, which is the compound named iron oxide.
Explanation:
Avery is experimenting with a simple circuit. She measures the current in the circuit three different times with a different battery each time. First, she uses a 1.5-volt battery. Next, she uses a 3-volt battery. Last, she uses a 9-volt battery. The resistance stays the same during each test. How did the current change for each test? Explain.
Answer: the current increases with each 3 volt and 9 volt. The relationship between resistance and current in a circuit is that the greater the resistance the less the current and the greater the current the less the resistance is. yayayay I could answer this I big brain :)
How large is the tension in a rope that is being used to accelerate a 100 kg box upward at 2m/s2?
[tex]\\ \sf\Rrightarrow T=F[/tex]
[tex]\\ \sf\Rrightarrow T=ma[/tex]
[tex]\\ \sf\Rrightarrow T=100(2)[/tex]
[tex]\\ \sf\Rrightarrow T=200N[/tex]
Oceanic crusts tend to be darker in color than continental crust. This is best explained by the fact that A) Oceanic crust is older than continental crust. B) Oceanic crust is denser than continental crust. C) Oceanic crust is thinner than continental crust. D) Oceanic crust is consist mostly of basalt while continental crust consist mainly of granite.
Answer:D
Explanation:USA test prep
Oceanic crusts tend to be darker in color than continental crust because
Oceanic crust consist mostly of basalt while continental crust consist mainly
of granite.
Oceanic crust are found under oceans while continental crust have most of
its parts above sea level. This explains why Oceanic crust is thinner than
continental crust due to the compression force from water.
Oceanic crust contains dark-colored rocks such as basalt while continental
crust contain light colored rocks such as granite which is why Oceanic
crusts tend to be darker in color than continental crust.
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A runner of mass 80 kg is moving at 8.0 m/s. Calculate her kinetic energy.
Answer:
2560J
Explanation:
By definition the kinetic energy can be calculated in the following way:
K = (mv²)/2 = 80kg·(8.0m/s)²/2 = 2560 J
explain the different conditions that can result in hot and cold lahars, and explain how lahars change the earth's surface?
the distance between student home and school is 1.5 km what is the distance traveld bythe students in a week
Answer:
10.5k
Explanation:
1.5x7=10.5
a ball of mass 0.15 kg is attached to one end of a string 1.10 m long. the ball moves in a horizontal circle with a speed of 12 m/s. determine the magnitude of the tension in the string
Answer:
[tex]19.64N[/tex]
Explanation:
Let's remember that if a mass describes a circle of radius [tex]l[/tex] with a constant speed of [tex]v[/tex], it has an angular velocity [tex]\omega=\frac vl[/tex]. in our case, our angular velocity will be of [tex]12/1.1= 10.91 rad/s[/tex].
Now that same mass will be subject of a centripetal acceleration [tex]a_c[/tex], caused of the tension of the string, equal to [tex]a_c=\omega^2l[/tex], which, in our situation, will be [tex](10.91)^2\times1.1=130.91 m/s^2[/tex]
We're almost done. We got mass, we got acceleration, the tension has to be their product: [tex]T= ma=130.91\times0.15=19.64N[/tex]
You are standing 30 m due east of a 50 kg person who is running at a speed of 20 m/s due west. What is the magnitude of that person's angular momentum about you (in units of )
Hi there!
We can use the following equation for angular momentum:
[tex]\large\boxed{L = mrv}[/tex]
m = mass (kg)
r = distance from reference point (m)
v = velocity (m/s)
We can simply plug-and-chug the values provided in the question.
L = (50)(30)(20) = 30000 kgm²/s
Destination is your Destination
Answer:
woah awesome so cool
Explanation:
Answer:
woah excellent!
A teacher took two latex balloons and blew them up with helium gas to the same size. She took one and labeled it Balloon A and placed it in a -15o C freezer. The second one she labeled BALLOON B, and she took it outside and tied it to the railing in the sun on a 30o C day. After a half hour, she had the students measure the circumference of each balloon. Which TWO outcomes do you predict the students will find and why?
Answer:
n
Explanation:
TWO outcomes can be predicted the students will find:
The size of balloon A becomes smaller.The size of balloon B becomes larger.What is the relation between temperature and volume of the gases?When a constant mass of gas is cooled, its volume falls, and when the temperature is raised, its volume grows. The volume of the gas rises by 1/273 of its initial volume at 0 °C for every degree of temperature rise.
In layman's words, the volume of a fixed mass of gas is exactly proportional to temperature at constant pressure.
The teacher took two latex balloons and blew them up with helium gas to the same size. As she placed Balloon A in a -15° C freezer, its temperature decreases and that's why, the size of balloon A becomes smaller. Again she placed Balloon B in the sun on 30° C day, its temperature increases and that's why, the size of balloon B becomes larger.
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That’s easy please tell me!
Energy can be changed from one form to another. Which terms can be used to describe these changes? Check all
that apply.
energy conversion
energy conservation
energy correlation
energy transformation
energy transference
Answer:
energy transformation
Answer: Energy Transformation & Energy Conversion.
Pleas help with question 25
Answer:
the answer is a....,.......
2- What is the kinetic energy in (N.m) and Joules of a 4Kg bowling ball rolling down a
bowling lane at 10 m/s? compare this energy with that of a 250g baseball traveling 50
m/s. which object would hurt more if it hit you (i.e., which object has the greater kinetic
energy)?
Happy Holidays!
Recall the equation for kinetic energy:
[tex]\large\boxed{KE = \frac{1}{2}mv^2 (J)}}[/tex]
m = mass (Kg)
v = velocity (m/s)
KE = kinetic energy (Nm or J)
We can find the kinetic energy for both the bowling ball and baseball:
Bowling ball:
[tex]\large\boxed{KE = \frac{1}{2}(4)(10^2) = 200 J}[/tex]
Baseball:
[tex]\large\boxed{KE = \frac{1}{2}(.25)(50^2) = 312.5 J}[/tex]
Since 312.5 J > 200 J, the BASEBALL has the greater kinetic energy. Thus, it would exert a greater impact force than the bowling ball, so it would hurt more.
5. average A body sets off from rest with a constant acceleration of 8.0 m/s? What distance will it have covered after 3.0 s? 6.
Answer:
[tex]\boxed {\boxed {\sf 36 \ meters}}[/tex]
Explanation:
We are asked to find the distance a body covers. We know the initial velocity, acceleration, and time, so we will use the following kinematic equation.
[tex]d= v_i t+ \frac {1}{2} \ at^2[/tex]
The body starts at rest with an initial velocity of 0 meters per second. The acceleration is 8 meters per second squared. The time is 3.0 seconds.
[tex]v_i[/tex]= 0 m/s a= 8 m/s²t= 3 sSubstitute the values into the formula.
[tex]d= (0 \ m/s)(3 \ s) + \frac{1}{2} (8 \ m/s^2)(3 \ s)^2[/tex]
Multiply the first set of parentheses.
[tex]d= ( 0 \ m/s * 3 \ s) + \frac{1}{2} ( 8 \ m/s^2)(3 \ s)^2[/tex]
[tex]d=0 \ m + \frac{1}{2} ( 8 \ m/s^2)(3 \ s)^2[/tex]
Solve the exponent.
(3 s)²= 3 s* 3 s= 9 s²[tex]d= 0 \ m + \frac{1}{2}( 8 \ m/s^2)(9 \ s^2)[/tex]
Multiply again.
[tex]d= 0 \ m + \frac{1}{2} ( 72 \ m)[/tex]
[tex]d= 36 \ m[/tex]
The body will cover a distance of 36 meters.
esse is swinging Miguel in a circle at a tangential speed of 3.50 m/s. If the radius of the circle is
0.600 m and Miguel has a mass of 11.0 kg, what is the centripetal force on Miguel? Round to the nearest whole number.
Answer:
Explanation:
F = mv²/R
F = 11.0(3.50²)/0.600 = 225 N
Which law of motion uses the formula mass = force x acceleration?
Answer:
Newton's second law
Explanation:
The part of the moon that is visible will appear to grow and shrink during the lunar cycle. This occurs in the direction of _____ to _____.
Answer:
left to right
Explanation:
give me brain pls
Answer:
of the moon to .......
The degree of coldness or hotness is different for different objects. Explain with an example
Answer:
Explanation:
The degree of hotness and coldness of air is known as temperature and is measured with a thermometer in degrees-Fahrenheit or degrees-Celsius. Mercury is the only one in the liquid state at room temperature. It is used in thermometers because it has a high coefficient of expansion. The flow of heat will be always from higher to lower temperature.
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