Answer:
u = 7.74 m/s and t = 1.82 s
Explanation:
Given that,
Harold threw a baseball 3 meters.
Harold is 2 meters tall.
The vertical distance = 3m
The final velocity at the maximum height is 0.
Let u is the initial velocity of the baseball. Using the first equation of motion to find it as follows :
[tex]v^2-u^2=2as[/tex]
Here, a = -g
[tex]v^2-u^2=-2gs\\\\u=\sqrt{2gs} \\\\=\sqrt{2\times 10\times 3} \\\\=7.74\ m/s[/tex]
He has thrown it with the speed of 7.74 m/s
Let t is the time taken by the ball to fall on the ground.
Harold is 2 meters tall. Using second equation of motion to find it.
u = -7.74 (as downward direction is taken as positive)
[tex]s=ut+\dfrac{1}{2}at^2\\\\2=-7.74t+5t^2\\\\t=1.82\ s[/tex]
Hence, this is the required solution.
Which of the following is the keyboard shortcut for saving a document?
O Control V
O Control S
O Control A
O Control E
Answer:Control S, Command S on MAC=Save
21. A teacher does the following:
i. walks 4 m, south
ii. walks 8 m, east
iii. walks 4 m, north
iv. walks 8 m, west.
The overall displacement of the teacher is
a. Om
b. 6 m
c. 12 m
d. ... Nonsense! It cannot be calculated without knowing time information.
Answer:
displacement is the change from a starting point. she ends up back where she started so her displacement is zero meters although she traveled 24m in all.
Electric power is to be generated by installing a hydraulic turbine-generator at a site 70 m below the free surface of a large water reservoir that can supply water at a rate of 1500 kg/s steadily. If the mechanical power output of the turbine is 800 kW and the electric power generation is 750 kW, determine the turbine efficiency and the combined turbine–generator efficiency of this plant. Neglect losses in the pipes.
Answer:
[tex]\eta_{turbine} = 0.777 = 77.7\%[/tex]
[tex]\eta_{combined} = 0.728 = 72.8\%[/tex]
Explanation:
First we calculate the power input to the turbine. The input power will be equal to the potential energy of water per unit time:
Input Power = [tex]P_{in} = \frac{Work}{Time} = \frac{Potential\ Energy\ of\ Water}{t} \\P_{in} = \frac{(mass)(g)(height)}{Time} = (mass flow rate)(g)(height)\\\\P_{in} = (1500\ kg/s)(9.81\ m/s^2)(70\ m)\\P_{in} = 1.03\ x\ 10^6\ W = 1030\ KW[/tex]
Now, for turbine efficiency:
[tex]\eta_{turbine} = \frac{Mechanical\ Power\ Out}{P_{in}}\\\\\eta_{turbine} = \frac{800\ KW}{1030\ KW}\\\\\eta_{turbine} = 0.777 = 77.7\%[/tex]
for generator efficiency:
[tex]\eta_{generator} = \frac{Power\ Generation}{Mechanical\ Power\ Out}\\\\ \eta_{generator} = \frac{750\ KW}{800\ KW}\\\\\eta_{turbine} = 0.9375 = 93.75\%[/tex]
Now, for combined efficiency:
[tex]\eta_{combined} = \eta_{turbine}\ \eta_{generator}\\\\\eta_{combined} = (0.777)(0.937)\\\eta_{combined} = 0.728 = 72.8\%[/tex]
Allison pulls on a refrigerator with 200 N of force. Fred helps
her out and pulls on the refrigerator in the same direction with
300 N of force. What is the net force on the refrigerator?
N
Answer:500
Explanation:
If two forces are acting on an object in the same direction, then they will add up and the net force will be the sum of their magnitudes. Thus, the net force on refrigerator is 500 N.
What is force?Force is an external agent acting on a body to deform it or to change it form the state of rest or motion. There are various kinds of forces, such as gravitational force, frictional force, magnetic force etc.
If two forces are acting on a on an object in the same direction, then they will add up and the net force will be the sum of their magnitudes. If they are acting from the opposite directions, they will cancel each other in magnitude and and the net force will be the subtracted value.
Here, both Allison and fred pulls the refrigerator from the same direction and the net force is the sum of forces by each person. Therefore, the net force here is 300 + 200 = 500 N.
To find more on net force, refer here:
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Question 6 (10 points)
The Washington Monument in our nation's capital is 555 ft high. Neglecting the effects of air resistance, what would be the
speed of the penny as it "hit" the ground?
оа
Ob
Oc
Od
48.3 m/s
-68.4 m/s
84.7 m/s
-57.6 m/s
Answer:
a= g = - 9.81 m/s2.
The following equations will be helpful:
a = (vf - vo)/t d = vot + 1/2 at2 vf2 = vo2 + 2ad
When you substitute the specific acceleration due to gravity (g), the equations are as follows:
g = (vf - vo)/t d = vot + 1/2 gt2 vf2 = vo2 + 2gd
If the object is dropped from rest, the initial velocity ("vi") is zero. This further simplifies the equations to these:
g = vf /t d = 1/2 gt2 vf2 = 2gd
The sign convention that we will use for direction is this: "down" is the negative direction. If you are given a velocity such as -5.0 m/s, we will assume that the direction of the velocity vector is down. Also if you are told that an object falls with a velocity of 5.0 m/s, you would substitute -5.0 m/s in your equations. The sign convention would also apply to the acceleration due to gravity as shown above. The direction of the acceleration vector is down (-9.81 m/s2) because the gravitational force causing the acceleration is directed downward.
hope this info helps you out!
Which three characteristics do mechanical waves and electrocmagnetic
waves share?
A. The waves begin with a disturbance.
O B. The waves transfer energy from its source.
C. The waves and their energy move outward from the source.
D. The waves and their energy can travel through empty space.
Answer:
It is A, B, and C
Explanation:
I just took the test!
The three characteristics mechanical waves and electromagnetic waves share are:
A. The waves begin with a disturbance.
B. The waves transfer energy from its source.
C. The waves and their energy move outward from the source.
What are mechanical waves and electromagnetic waves?Usually, waves transfer energy from one place to another. Mechanical waves transfers via matter where as electromagnetic waves transfers via light. Both mechanical waves and electromagnet (light) waves measured through amplitude, wavelength, frequency and both will get transmitted, refracted, reflected, absorbed, diffracted when they react with matter. Both the electromagnetic waves and mechanical waves are transverse in nature but the mechanical waves can also be in longitudinal.
So, many characteristics were similar for mechanical waves and electromagnetic waves.
Hence, Option A, B, C are the three characteristics.
Learn more about the waves,
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How do ions help your brain?
The force of air particles over an area is ________
temperature.
pressure.
volume.
kelvins.
Help me pretty please with a cherry on top!!
Answer:
A. im not for sure hope it helps
Explanation:
I WILL MAKE U BRAINLIEST PLEASE ANSWER !!!!!!!!
Venmoing if answered —
ANSWER PLS ! 15 POINTS!
Question: If you are traveling by train and the trip is 125 miles and takes 2 hours winding through the mountains, a) whats average speed? b) how would this be different if the train in each of the following situations- Train at rest, Train traveling at constant speed in a straight line, and the Train with a braking force (the train in the middle of coming to a stop)
PLEASE ANSWER ALL ASAP
Answer:
Average speed 62.5 miles an hour. If the train was traveling at a constant speed in a straight line it would be much faster on getting to its destination
Explanation:
type of energy found in bread
Answer:
Bread contains energy in form of
Carbohydrates
Explanation:
Answer:
CHEMICAL ENERGY
how longitudinal waves are formed
Answer:
forever
Explanation:
A stone takes 5.4 seconds to fall from the top of a cliff. The cliff is
meters high.
143
53
286
573
Answer:
143
Explanation:
Using one of the 3 fundamental equations in physics, y=vo*t+1/2gt^2, we can use this equation to find the total distance that was traveled.
Acceleration due to gravity is always 9.8m/s^2 and time is 5.4s, we also have no initial velocity.
Given this, we can plug in the known variables.
y=0t+1/2*9.8*5^2
simplify,
y=4.9*5.4^2
y=4.9*29.16
y=142.884m which we can round up to 143 meters
Final Answer: 143 meters
if you punch a wall with the force of 30N, what force will you feel on your fist
30N
Natural reaction, the same force comes back to you
Answer:
it depends on if collision elastic or in elastic
if collision is elastic the the wall will also exert 30 N
Particles in which state of matter are the most likely to interact with each other to cause a chemical reaction?
A 20 kg mass is hanging on one side of a pulley and a 5 kg mass is hanging on the other. Determine the acceleration of each mass.
Answer:
i believe it's 7
Explanation:
Should the resistance of an ammeter low or high ?give reason
Answer:
The resistance of an ammeter should be low. This is because an ammeter is connected in series with the circuit for the measurement of electric current. In case, its resistance is high, then some amount of current may lost in heating it leading to the inaccurate reading. An ideal ammeter is one which has zero resistance.
Plz do all of it i will give brainlest and thanks to best answer
plz do it right
Answer:
d
Explanation:
Answer:
Earth absorbs heat from the sun.
Explanation:
This radiation is absorbed by greenhouse gases which then radiate energy into all directions including downwards and thereby trapping heat in the atmosphere.
Hope you have a good day :)
A rat runs 2m right, turns around and runs 3m left. Then goes 2m right. What is its displacement?
A. 1m right
B. 1m left
C. 7m
D. 7m left
Answer:
Explanation:
I think this answer would be 1m to the left.
How do I calculate how many meters are in 7.2 light years?
The exact question is:
Calculate in meters the distance between a galaxy and the Earth if the distance is equal to 7.2 light years.
Answer:
68.2 Quadrillion meters
Explanation:
A lightyear is the distance that light travels in one year.
Speed of light is [tex]3*10^8\ m/s[/tex]
So light covers 300,000,000 meters in one second.
One year has 31536000 seconds so , light covers
[tex]9.461*10^{15}\ meters\ in\ one\ year[/tex]
so 7.2 light years is
[tex]7.2*(9.461*10^{15})\\6.82*10^{16}[/tex]
so 7.2 light years is
6.82 x 10^(16) meters or
68.2 Quadrillion meters
Help please!!!
if superman at 90kg jumps a 40m building in a single bound how much work does superman perform
Answer:
5 years worth of work (aka all of the homework i currently have)
Which one is an example of a force pushing downward toward the ground.
Group of answer choices
A man pulled weeds in his garden
A woman moved her child from one place to another in a wagon
A bird sat on a telephone wire
A dog tugged on a rope held by a child
Answer: A woman moved her child from one place to another in a wagon
or A bird sat on a telephone wire
Explanation:
A duck is floating in a pond. How does Archimedes' description of the buoyant force explain why the duck
doesn't sink?
PLEASE HURRY
Answer:
The upthrust or buoyant force helps the duck doesn't sink.
For example, there is a duck which weighs 3 pounds and tree pints of water also weigh three pounds. In this case the volume of the duck is more than the volume of three pints of water, so the duck floats.
Hope it helps!<3
If a refrigerator draws about 0.5 amps when plugged into a 120 V wall outlet how much power (watts) does it use?
Answer:60 W
Explanation:
An object weighing 49 N is pushed across a floor by a force of 12 N. What is the acceleration of the object?
Answer:
Explanation:
Given parameters:
Weight of object = 49N
Force applied = 12N
Unknown:
Acceleration of object = ?
Solution:
The acceleration of the object is found by dividing the force by the weight;
Acceleration = [tex]\frac{12}{49}[/tex] = 0.25m/s²
PLZ HELP ME
Which event was a major source of atmospheric oxygen?
photosynthesis
decomposition of water
volcanic eruptions
outgassing
Answer:
photosynthesis
Explanation:
I just took the midterm and got it correct :))
PLZ MAKE BRAINLIEST, thank youuu <3
Cardiovascular fitness measures the health of which body system?
Answer:
I believe it is the circulatory system.
Explanation:
Have a nice day.
where does reduction occur in an electrolytic cell
a. cathode
b. salt bridge
c. anode
d. wire
Answer:
The answer is actually a. Cathode
Explanation:
Just took the quiz
In an electrolytic cell, the reduction occurs at the cathode. So, the correct option is a.
What is meant by reduction ?Reduction is defined as the process through which a reactant gain electrons during a chemical reaction.
Here,
An electrolytic cell is an equipment that uses electric current to drive a redox reaction.
Redox reactions are the type of reaction that involves the transfer of electrons between the reactants. That means, in redox reactions, both oxidation and reduction occurs. The reactant that gains the electrons is said to be reduced and the one that losses the electrons is said to be oxidized.
In an electrolytic cell, cathode is the positively charged electrode. So, electrons are attracted towards it, and as a result, the cathode gets reduced.
Hence,
In an electrolytic cell, the reduction occurs at the cathode.
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what power is transmitted by 2A flowing across 5V
Answer:
[tex]\huge\boxed{10\:watts}[/tex]
Explanation:
Power = Current × Voltage
P = I × V
P = 2 × 5
P = 10 watts
Guys i need help please
Answer:
I'm pretty sure the answer is around 9.2 seconds
Explanation:
