Answer:
a. Vf = 39.24 [m/s]
b. Vf = 31.24 [m/s]
c. Vf = 47.24 [m/s].
Explanation:
To solve this problem we can use the following equation of kinematics. We have to keep in mind that the gravitational acceleration acts downwards, therefore when the rock falls towards the abyss it has the same direction of the acceleration and that is why the gravitational acceleration has a positive sign in the equation.
[tex]v_{f}=v_{o}+g*t[/tex]
where:
Vf = final velocity [m/s]
Vo = initial velocity = 0 (when the rock is dropped)
g = gravitational acceleration = 9.81 [m/s²]
t = time = 4 [s]
a.
[tex]v_{f}=0+9.81*4\\v_{f}= 39.24 [m/s][/tex]
b.
In this particular situation, the acceleration will be taken as negative because the gravity is pointing in the opposite direction of the movement of the rock.
[tex]v_{f}=8-(9.81*4)\\v_{f}=-31.24[m/s][/tex]
The negative sign in the answer tells us that the rock no longer moves up instead it does downwards when 4 seconds have passed.
c.
[tex]v_{f}=8+(9.81*4)\\v_{f}=47.24[m/s][/tex]
The negatively charged particle in an atom is a(n):
Answer: Electron
Explanation:A negatively charged particle found circling or orbiting an atomic nucleus. An electron, like a proton is a charged particle, although opposite in sign, but unlike a proton, an electron has negligible atomic mass. Electrons contribute no atomic mass units to the total atomic weight of an atom.
Hope this helps!!Brainlist?
A grinding wheel, initially at rest, is ro-tated with constant angular acceleration of2.52 rad/s2for 7.03 s. The wheel is thenbrought to rest with uniform deceleration in11.9 rev.Find the angular acceleration required tobring the wheel to rest. Note that an in-crease in angular velocity is consistent with apositive angular acceleration.Answer in units of rad/s2.
Starting from rest, the wheel accelerates to an angular velocity of
ω = (2.52 rad/s²) (7.03 s) ≈ 17.7 rad/s
then undergoes a new acceleration α until it comes to a rest. It does so in 11.9 revolutions, or with an angular displacement of (11.9 rev) • (2π rad/rev) = 23.8π rad. So α satisfies
0² - ω² = 2 α (23.8π rad)
α = - ω² / (47.6π rad)
α ≈ -2.10 rad/s²
some sedimentary rocks are made from smaller rounded stones that have been cemented together called what?
A: Intrusive rock
B: conglomerate rock
C: extrusive rock
D: marble
Answer:
B.
Explanation:
Intrusive and extrusive rocks are igneous rocks and marble is metamorphic, by the process of elimination, B would be the correct answer.
Answer:
answer is B
Explanation:
Mr. Davis is riding his bike at a speed of 5 meters per second for 3600 seconds how far did he ride?
Answer:18,000 meters
Explanation:3600x5=18,000.
what are the uses of X-rays.
Explanation:
id : 237 514 2470
pass : frmCV5
Join in zoom!❤
I am boy :)
If a small motor does 520 J of work to move a toy car 260 m in 3.0 seconds, how much power is being applied by the motor?
Answer:
P = 173.33 [W]
Explanation:
Power is defined as the amount of work done over a given time.
W = work = 520 [J]
t = time = 3 [s]
P = power [w]
Therefore by working relationship over time we can calculate the power.
[tex]P =W/t\\P = 520/3\\P=173.33[W][/tex]
A mirror forms an erect image of 30 cm from the object and a fifth of its height. Where must the mirror be situated? What is its radius of curvature? Assuming the object is to be real, determine whether it is convex or concave
concave
Explanation:
convex would magnify
Why do humans to experience the four seasons
Answer:
As the earth spins on its axis, producing night and day, it also moves about the sun in an elliptical (elongated circle) orbit that requires about 365 1/4 days to complete. The earth's spin axis is tilted with respect to its orbital plane. This is what causes the seasons.
Explanation:
what do you know about atom
Answer:
The smallest part of the elements which contains matters in them are atoms :)
a projectile is fixed from ground level with a velocity 500m/s at 30 degree to the horizontal .find its horizontal range, the greatest height and time to reach the greatest height.
Answer:
1. 22092.31 m
2. 3188.78 m
3. 25.51 s
Explanation:
Let's split this projectile's motion into its horizontal and vertical components:
Horizontal (v_x) component: 500 * cos(30)Vertical (v_y) component: 500 * sin(30)Since this projectile is in constant acceleration (9.8 m/s² vertically downwards and 0 m/s² horizontally), we can use the kinematic equations for constant acceleration.
Let's find the time it takes for the projectile to reach its greatest height first by using our knowledge that, at the top of its trajectory, the projectile will have a final velocity of 0 m/s before changing its direction and falling down.
Therefore, we can use the equation that contains the variables a_y, v_f, v_i, and t in order to solve for time t.
This equation is: v = v_0 + at, where v is the final velocity, v_0 is the vertical component of the initial velocity, a is the acceleration in the y-direction, and t is the time of flight of the projectile.
Plug known values into the equation:
0 = 500 * sin(30) + (-9.8)tSubtract 500 * sin(30) from both sides of the equation.
-500 * sin(30) = -9.8tDivide both sides by -9.8.
t = 25.51The time it takes the projectile to reach its greatest height is 25.51 seconds.
Now we can use this time t to find the greatest height of the object, which will be the displacement in the y-direction at t = 25.51 seconds.
We can use this equation that contains the variables displacement (Δx), initial velocity (v_0), acceleration (a_y), and time (t):
Δx = v_0 t + 1/2at²Plug known values into the equation.
Δx = [500 * sin(30)] * 25.51 + 1/2(-9.8)(25.51)² Δx = 6377.5 + -4.9 * 650.7601 Δx = 6377.5 + -3188.72449 Δx = 3188.77551The displacement in the y-direction is 3188.78 m at half the time t, meaning that this is the greatest height of the projectile.
Now we can find the horizontal range of the projectile by using the same equation, but this time in the x-direction.
Δx = v_0 t + 1/2at²We will use the x-component of the initial velocity and the acceleration in the x-direction, which is always 0 m/s² assuming air resistance is negligible. Note that the time we have above (25.51 sec) is only half the total time, so we will use double this time (51.02 sec).
Δx = [500 * cos(30)] * 51.02Δx = 22092.31The horizontal range of the projectile is 22092.31 m.
We only see objects because they absorb light.
True or False?
Answer:
true
Explanation:
i think it's true because I took a quiz on this
how did Albert Einstein come up with 3 = mc square pls help
Answer: He came up with this by using theories like the photoelectric effect, the second offered experimental proof of the existence of atoms, and the third introduced the theory of special relativity.
Explanation: He was explaing the realationship between energy and mass.
Me: Hope this helps!!! May I have brainlist!?
Electricity costs 10p per unit. How much will it cost Sam to use a 85W laptop and a 60W lamp for an hour?
It will cost Sam "1.45 p. per hr" to use an 85W laptop and a 60W lamp. To understand the calculation, check below.
Power and ElectricityAccording to the question,
Electricity cost = 10 p per unit
Laptop power = 85 W
Lamp power = 60 W
We know the standard unit, KW/hr = 1000 W/hr
then,
= 85 + 60
= 145 W
By fractioning,
= [tex]\frac{145}{1000}[/tex]
= 0.145 KWH
hence,
The cost will be:
= 0.145 × 10 p
= 1.45 p. per hr
Thus the above approach is correct.
Find out more information about electricity here:
https://brainly.com/question/11517288
What do the lysosomes do? (check all that apply)
A) clean the cell
B) ship products
C) destroy foreign objects
D) provides energy for the cell
Answer:
I think its A
Explanation:
A lysosome is a membrane-bound cell organelle that contains digestive enzymes. Lysosomes are involved with various cell processes. They break down excess or worn-out cell parts. They may be used to destroy invading viruses and bacteria.
The function of lysosomes is to remove waste as well as destroying a cell after it has died, called autolysis. A lysosome is an organelle containing digestive enzymes which it uses to function as the digestion and waste removal for cells, food particles, bacteria, etc.
Particle moves in a circle of radius 90m with a constant speed 25m/s. how many revolution does it make in 30sec
Answer:
n =1.33 revolutions
Explanation:
Uniform Circular Motion
The angular speed can be calculated in two different ways:
[tex]\displaystyle \omega=\frac{v}{r}[/tex]
Where:
v = tangential speed
r = radius of the circle described by the rotating object
Also:
[tex]\omega=2\pi f[/tex]
Where:
f = frequency
Solving for f:
[tex]\displaystyle f=\frac{\omega}{2\pi}[/tex]
Since the frequency is calculated when the number of revolutions n and the time t are known:
[tex]\displaystyle f=\frac{n}{t}[/tex]
We can solve for n:
n=f.t
The particle moves in a circle of r=90 m with a speed v=25 m/s. Thus the angular speed is:
[tex]\displaystyle \omega=\frac{25}{90}[/tex]
[tex]\displaystyle \omega=0.278\ rad/s[/tex]
Now we calculate f:
[tex]\displaystyle f=\frac{0.278}{2\pi}[/tex]
[tex]f=0.04421\ Hz[/tex]
Calculating the number of revolutions:
n = 0.04421*30
n =1.33 revolutions
what does the area under a speed-time graph represent
Answer: It represents the whole distance traveled. Hope this helps!
Explanation:
When a 54.9-g tennis ball is served, it accelerates from rest to a speed of 45.1 m/s. The impact with the racket gives the ball a constant acceleration over a distance of 35.1 cm. What is the magnitude of the net force acting on the ball
Answer:
F = 159.07 N
Explanation:
Given that,
Mass of a tennis ball, m = 54.9 g = 0.0549 kg
It accelerates from rest to a speed of 45.1 m/s.
The impact with the racket gives the ball a constant acceleration over a distance of 35.1 cm = 0.351 m
We need to find the magnitude of net force acting on the ball.
Let a be the acceleration of the ball. Using third equation of motion to find it.
[tex]v^2-u^2=2ad\\\\a=\dfrac{v^2-u^2}{2d}\\\\a=\dfrac{(45.1)^2-(0)^2}{2\times 0.351}\\\\=2897.45\ m/s^2[/tex]
Net force,
F = ma
F = 0.0549 kg × 2897.45 m/s²
= 159.07 N
Hence, the net force acting on the ball is 159.07 N.
What force is required to give an object with mass 50 kg an acceleration of 8 m/s2 O A. 6.25 N O B. 58 N O C, 400 N O D, 250 N
Answer:
C, 400 N
Explanation:
Given parameters:
Mass of object = 50kg
Acceleration = 8m/s²
Unknown:
Amount of force = ?
Solution:
According to Newton's second law of motion;
Force = m a
m is the mass
a is the acceleration
Now insert the parameters and solve;
Force = 50 x 8 = 400N
Which of Earth's Layers is solid but still "bendable"?
Answer:
Mantlee
Explanation:
Which of the four spheres is this pictures/scene?
A) hydrosphere
B) biosphere
C) geosphere
D) atmosphere
I believe the correct answer is atmosphere (D).
Answer:
D) atmosphere
Explanation:
but the correct answer is troposhare
All of the following are types of models EXCEPT
O a theory.
Dan analogy.
Oa physical replica.
O a mathematical representation.
Answer:
A theory
Explanation:
No, the person who answered above is incorrect. I just took the assessment and I can guarantee you the answer is "a theory".
-Lexi
The type of charge on an object depends on what? Material of object quality of object force of rubbing thickness of object please tell
Explanation:
Type of charge on an object depends upon the material of the object. However, most of the material are electrically neutral. Since, they have equal number of positive and negative charges on them. So, they act as if they have no charge at all.
Hence, option A is correct.
1) Think of planting a tree. You dig the hole, put it in, and fill it back in. Next,
you need to attach 3 ropes to the tree to try to keep it straight while it grows.
You put the ropes on it like a "V". Where do you have to put the third rope to
ensure your tree is straight?
Answer:
at the top of the tree I hope it will help you please follow me
What is S.I units?
Answer:
Explanation:
he SI rests on a foundation of seven (7) defining constants: the cesium hyperfine splitting frequency, the speed of light in vacuum, the Planck constant, the elementary charge (i.e. the charge on a proton), the Boltzmann constant, the Avogadro constant, and the luminous efficacy of a specified monochromatic source. Definitions of all seven (7) SI base units are expressed using an explicit-constant formulation and experimentally realized using a specific mises en pratique (practical technique).
The seven SI base units, which are comprised of:
Length - meter (m)
Time - second (s)
Amount of substance - mole (mole)
Electric current - ampere (A)
Temperature - kelvin (K)
Luminous intensity - candela (cd)
Mass - kilogram (kg)
The International System of Units (SI), commonly known as the metric system, is the international standard for measurement. The International Treaty of the Meter was signed in Paris on May 20, 1875 by seventeen countries, including the United States and is now celebrated around the globe as World Metrology Day. NIST provides official U.S. representation in the various international bodies established by the Meter Convention: CGPM - General Conference on Weights and Measures; CIPM - International Committee for Weights and Measures; and BIPM - The International Bureau of Weights and Measures.
The SI is made up of 7 base units that define the 22 derived units with special names and symbols. The SI plays an essential role in international commerce and is commonly used in scientific and technological research and development. Learn more about the SI in NIST SP 330 and SP 811.
Resources for Students and Teachers
Redefining the SI – In November 2018, the world’s measurement experts voted and unanimously approved a revision of the SI that establishes a measurement system entirely based on physical constants of nature. The changes became effective on World Metrology Day, May 20, 2019. (NIST)
Learn more about the Road to the Revised SI. Learn more about the SI Redefinition.(NIST)
The Last Artifact documentary and companion Grade 5 to 12 educational resources, which document the work that went on behind the scenes to modernize the International System of Units (SI). (Montana PBS)
NIST SP 1247 SI Base Units Relationships Poster – a colorful poster illustrating the relationships of the International System of Units (SI) derived units with special names and symbols and the seven traditional base units. (NIST)
Metric Trivia Quiz – How much do you know about the metric system (SI)? Try the NIST Metric Trivia Quiz online or use the Alexa skill to test your knowledge and be on your way to thinking metric! (NIST)
SI Education and Training – Explore NIST metric system education resources that build SI measurement system familiarity and fluency. (NIST)
Kids Education Resources. (NIST)
Busting Myths about the Metric System. (NIST Taking Measure Blog)
Resources
Becoming Familiar with SI
Everyday Estimation
Metrication FAQs
Prefixes
SI Publications
Understanding Metric
Writing with Metric Units
Answer:
International System of Units??
A student presses her palm by her thumb with a force of 75 N . What would be the pressure under her thumb having contact area is 1.5 cm2
Answer:
Pressure = 50 N/cm²
Explanation:
Given:
Force = 75 N
Area = 1.5 cm²
Find:
Pressure
Computation:
Pressure = Force / Area
Pressure = 75 / 1.5
Pressure = 50 N/cm²
If you are holding a stack of books at your waist and then you walk across the room your hands did?
1) efficiency
2) power
3) work
4) no work
Answer:
3. Work
Explanation:
Number 1 isn't correct because you are not using efficiency to hold books and walk across the room.
Number 2 could be correct but isn't in this situation because you use power only to hold the books but not to walk across the room.
Number 4 is not correct because you need to do work to do something.
A balloon drifts 14 km at an angle of 30º to the ground. What is the vertical component of the balloon
Sin is the vertical component. So multiply sin 30 and 14. BOOM! You got the answer.
[tex] \sin(30) \times 14 \: = 7[/tex]
A bullet of mass 4.0g is fired from a rifle of mass 2.0kg with muzzle velocity of 380m/s. What is the initial recoil velocity of the rifle?
Answer:
v = 0.76 [m/s]
Explanation:
The linear momentum generated by the shot must be calculated. This can be calculated using the following expression.
[tex]P=m*v\\[/tex]
where:
P = linear momentum [kg*m/s]
m = mass [kg]
v = velocity [m/s]
[tex]P=0.004*380\\P=1.52[kg*m/s][/tex]
Now we can calculate the recoil velocity, because the momentum is equal for the rifle.
[tex]P=m*v\\v = P/m\\v = 1.52/2\\v = 0.76[m/s][/tex]
7. What force is required to accelerate a 100 kg car to 4 m/s27 F=ma
O A. 25N
B. 104N
C. 400N
Answer:
is the formula is F=MA so
F=100kg×4m/s=400n
so the answer is 400n
It is not possible to accurately calculate instantaneous velocity.
TRUE
FALSE
