Answer:
(a) Let the height of the platform is h meter,
=>By s = ut + 1/2gt^2
=>h = 0 + 1/2 x 9.8 x (2.3)^2
=>h = 25.92 m
(b) By R = [Ux] x t
=>R = 2.47 x 2.3
=>R = 5.68 m
Explanation:
Explanation:
From the exercise we know the initial horizontal velocity and the time that Janet takes to land in the water
a) Knowing the formula for free falling objects, we can calculate how high is the platform
At t=2.3m the position of Janet is y=0m
So, the platform is 26m tall
b) According to dynamics the displacement of an object can be analyze using the following formula:
So, Janet lands 6 m far from the base of the platform
A fireboat is to fight fires at coastal areas by drawing seawater with a density of 1030 kg/m3 through a 10-cm-diameter pipe at a rate of 0.04 m3/s and discharging it through a hose nozzle with an exit diameter of 5 cm. The total irreversible head loss of the system is 3 m, and the position of the nozzle is 3 m above sea level. For a pump efficiency of 70 percent, determine the required shaft power input to the pump and the water discharge velocity.
Answer:
50.93 m/s
199.5 kW
Explanation:
From the question, the nozzle exit diameter = 5 cm, Radius= diameter/2= 5cm/2= 2.5cm. we can convert it to metre for unit consistency= (2.5×0.01)=
0.025m
We can calculate the The cross sectional area of the nozzle as
A= πr^2
A= π ×0.025^2
= 1.9635 ×10^- ³ m²
From the question, the water is moving through the pipe at a rate of 0.1 m /s , then for the water to move through it at a seconds, it must move at
(0.1 / 1.9635 ×10^- ³ m²)
= 50.93 m/s
During the Operation of the pump, the Dynamic energy of the water= potential energy provided there is no loss during the Operation
mgh = 1/2mv²
We can make "h" subject of the formula, which is the height of required head of water
h = (1/2mv²)/mg
h= v² / 2g
h = 50.93² / (2 ×9.81)
h = 132.21m
From the question;
The total irreversible head loss of the system = 3 m,
the given position of nozzle = 3 m
the total head the pump needed=(The total irreversible head loss of the system + the position of the nozzle + required head of water )
=(3 + 3 + 132.21m)
=138.21m
mass of water pumped in a seconds can be calculated since we know that mass is a product of volume and density
Volume= 0.1m³
Density of sea water=1030 kg/m
(0.1 m^3× 1030)
= 103kg
We can calculate the Potential enegry, which is = mgh
= (103 ×9.81 × 138.21)
= 139651.5 Watts
= 139.65kW
To determine required shaft power input to the pump and the water discharge velocity
Energy= efficiency × power
But we are given efficiency of 70 percent, then
139651.5 Watts = 0.7P
=199502.18 Watts
P=199.5 kW
Therefore, the required shaft power input to the pump and the water discharge velocity is 199.5 kW
Particles in which state of matter are the most likely to interact with each other to cause a chemical reaction?
Which type of wave transfers energy in the same way as a sound wave?
A
Radiation wave
B.
Seismic wave
C.
Heat wave
D.
Light wave
Answer:
Radiation wave
Explanation:
These the flow of electrons (the current) and where some of the electrons' energy gets converted into heat. (Lessons 5.01-5.03) electric currents Insulators Resistors Conductors
Answer: The answer is resistors
Explanation: I just took the unit test and it was correct
what is the kinetic energy of a 1 kilogram ball thrown into the air with an initial velocity of 30 m/s
Explanation:
KE = 1/2 MV ^2
KE = 1/2 * 1 * 30 ^2
KE= 1/2 * 1 * 900
KE = 450 kg m^2/ s^2
please mark me as a brainelist
Answer:
the above pic will help
I have done it in word
I hope it helps mate
mark me brainliest plsss
I will always help you understanding your assingments
have a great day
#Captainpower:)
Question 1 of 25
A bookcase has a mass of 37 kg. What is the weight of the bookcase?
Help please
answers
81.6 pounds rounded or just 81.571 if it needs to be exact
If the atomic weight- # of protons = # of neutrons, then how many neutrons does neon have?
Answer:
atomic weight 20.180
protons 10
neutrons 2,8
Explanation:
What is the density of an object with a mass of 20 grams and a volume of 5 cm?
Answer:
4
Explanation:
Divide mass(m) by volume(v), you get density(D)
m/v=D
20/5=4
This image shows flashlight beams reflecting off a mirror from
different angles. Based on the angles of reflection, choose all pairs of
light rays that correctly match incoming light beams with their
reflected light beams,
Question 2. Based on the image and the angles of reflection shown witch statement is true.
A) When a light ray strikes a mirror, it randomly scattered.
B) light is absorbed by mirrors and reflected directly upwards.
C) light travels in a straight line until lit strikes an object
D) light is reflected back to its source when it strikes an object
Hey I'm working on this test right now, did you ever get the answers?
12. How many grams of beryllium are needed to produce 36.0 g of hydrogen? (Assume an excess of water.)
Be(s) + 2H, O() → Be(OH)2 (aq) +H,(g)
a
4.00 g
b. 36.0 g
c. 162 g
d 324 g
Answer:
Answer is: 162 g of beryllium.
Chemical reaction: Be + 2H₂O → Be(OH)₂ + H₂.
m(H₂) = 36,0 g.
m(Be) = ?
n(H₂) = m(H₂) ÷ M(H₂)
n(H₂) = 36,0 g ÷ 2 g/mol = 18 mol.
from reaction: n(Be) : n(H₂) = 1 : 1.
n(Be) = n(H₂) = 18 mol.
m(Be) = n(Be) · M(Be).
n(Be) = 18 mol · 9 g/mol = 162 g.
Answer:
Answer is: 162 g of beryllium.
Chemical reaction: Be + 2H₂O → Be(OH)₂ + H₂.
m(H₂) = 36,0 g.
m(Be) = ?
n(H₂) = m(H₂) ÷ M(H₂)
n(H₂) = 36,0 g ÷ 2 g/mol = 18 mol.
from reaction: n(Be) : n(H₂) = 1 : 1.
n(Be) = n(H₂) = 18 mol.
m(Be) = n(Be) · M(Be).
n(Be) = 18 mol · 9 g/mol = 162 g.
How to find acceleration?
Answer:
a=(v-u)/t is how you find acceleration.
Find the displacement of the object moving at v= -2 m/s for t=5s
Answer:
d = - 10 [m]
Explanation:
We must remember that speed is defined as the relationship between the displacement in a given time. In this way, we can propose the following equation.
[tex]v = d/t[/tex]
where:
v = velocity = 2 [m/s]
d = displacement [m]
t = time = 5 [s]
Now replacing:
[tex]d=-5*2\\d=-10[m][/tex]
Help me pretty please with a cherry on top!!
Answer:
A. im not for sure hope it helps
Explanation:
Keith has been using a software application for a year on his home computer. A new version of the application was recently released. Keith’s license has a term of two years and entitles Keith to upgrade his application to a new version within the term. What type of license does the application have?
Answer:
d license with maintenance .
Explanation:
just took this test. :)
You use a lever to lift a heavy tree branch. You apply a force of 30 N and the
lever lifts the branch with a force of 120 N. What is the mechanical advantage
of the lever?
A. 4
B. 0.25
C. 2
D. 90
Answer:
D 90 subtract it
Explanation:
A 35kg cannonball sits at rest on a flat level surface. What is the normal force exerted on the cannon ball. Use -9.8 m/s2 for acceleration due to gravity.
A. -343N
B. 44.8N
C. 25.2N
D. 343N
Answer:
a) N = 343 [N]
Explanation:
We must remember Newton's third law, which tells us that the force acting on a body is equal to the normal reaction force of equal magnitude but acting in the opposite direction.
[tex]N=m*g[/tex]
where:
m = mass = 35 [kg]
g = gravity acceleration = 9.81 [m/s²]
[tex]N = 35*9.8\\N= 343 [N][/tex]
How does the electric force between two charged particles change if the
distance between them is reduced by a factor of 2?
A. It is reduced by a factor of 2.
B. It is increased by a factor of 4.
C. It is increased by a factor of 2.
D. It is reduced by a factor of 4.
Answer:
increased by a factor of 4
Explanation:
A gun fires a bullet horizontally with a velocity of 90 m/s from a tower. Neglecting air resistance, how far will the bullet travel horizontally in 4 seconds?
Answer:
The distance covered along the horizontal axis is [tex]s = 360 \ m[/tex]
The distance covered along the vertical axis is [tex]h = 78.4 \ m[/tex]
Explanation:
From the question we are told that
The horizontal velocity is [tex]u_x = 90 \ m/s[/tex]
The time considered is [tex]t = 4 \ s[/tex]
Generally the distance which the bullet will cover in the horizontal direction for the given time is mathematically represented as
[tex]s = u_xt + \frac{1}{2}* at^2[/tex]
Here a is the acceleration along the horizontal direction and the value is [tex]a = 0 \ m/s^2[/tex]
So
[tex]s = 90 * 4 + \frac{1}{2}* * 0 * 4^2[/tex]
=> [tex]s = 360 \ m[/tex]
Generally the distance which the bullet will cover in the vertical direction for the given time is mathematically represented as
[tex]h= u_y t + \frac{1}{2}* gt^2[/tex]
Here [tex]u_y[/tex] is the initial velocity of the bullet along the vertical axis and the value is [tex]u_y = 0 \ m/s[/tex]
[tex]h = 0 * 4 + \frac{1}{2}* 9.8 *4^2[/tex]
=> [tex]h = 78.4 \ m[/tex]
A pulse with a height of 20 cm and a length of 30 cm travels with a speed of 400 cm/s through a spring that has been stretched so it is 800 cm long. If we want to send another pulse through the spring that will have a different speed, which of the bolded words should we change? List all that will change the speed of the wave.
Answer:
To send a pulse of different speed, change the tension or stretch on the spring
Explanation:
A pulse is a single disturbance of a particle is a medium. The pulse has an amplitude or and a pulse length in the medium. The speed of the pulse is dependent on the amount of strain or tension ( stretch) applied to the medium. The speed also determines the length of the pulse but is unaffected by the or amplitude of the pulse.
Light that enters your eye strikes cells in the back of your eye
true
False
Answer: True
Explanation: Light enters your eye through the lens which then hits the retina which is located in the back of your eye.
41. What effects the efficiency of a pulley?
a. the type of rope or cable
b. the way the wheel turns
c. the length of the rope
d. how big the wheel is
e. only a and be
f. all of the above
Answer:
e. only a and b
A supply plane drops a package to the ground for stranded campers below. After falling for 8.14 seconds, the package will have a downward velocity of 80.79 m/s. How high was the plane when it dropped the package?
Answer:
333 m
Explanation:
The following data were obtained from the question:
Initial velocity (u) = 0 m/s.
Time (t) = 8.14 s.
Final velocity (v) = 80.79 m/s.
Acceleration due to gravity (g) = 9.8 m/s²
Height (h) =?
v² = u² + 2gh
80.79² = 0 + (2 × 9.8 × h)
6527.0241 = 0 + 19.6h
6527.0241 = 19.6h
Divide both side by 19.6
h = 6527.0241 / 19.6
h = 333 m
Thus, the plane was at a height of 333 m when the package was dropped.
HELP ASAP TIMER
Your younger brother gets a new toy car as a present. He winds up the toy, puts it on the ground and watches it accelerate for 5 seconds. You can explain how to find the net force acting on the toy car for the 5 seconds while accelerating by the following:
a
Use a meterstick and stopwatch to measure the distance the car travels for the 5s.
b
Use a balance to determine the mass of the car. Use a motion sensor to measure the speed of the car at a time of 0s and at time of 5s .
c
Use a balance to determine the mass of the car. Use a meterstick to measure the distance the car travels for the 5s .
d
Use a motion sensor to measure the speed of the car at a time of 0s and a time of 5s . Use a meterstick to determine the distance the car travels for 5s .
Answer:
b Use a balance to determine the mass of the car. Use a motion sensor to measure the speed of the car at a time of 0s and at time of 5s .
Explanation:
The right way to measure the net force on the car is take the measurement of its mass then find the speed of the car within the time 0s to 5s.
This is because the net force acting on car is given as;
Force = mass x acceleration
By using the balance, the mass is determine
Acceleration is the rate of change of velocity with time.
Acceleration = [tex]\frac{v - u}{t}[/tex]
v is the final velocity
u is the initial velocity
t is the time taken
Now,
Force = mass x [tex]\frac{v - u}{t}[/tex]
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:
Name the following ionic compounds: BeCl2
Answer:
Beryllium chloride
Explanation:
I hope this helps!
Can I get branliest?!
When a person strikes and lights a match, potential energy in the match is transformed into which types of energy?
electrical and thermal
thermal and radiant
radiant and nuclear
nuclear and kinetic
hurry brainliest ill give 49 points
Answer:
Radiant and thermal
Explanation:
Electrical and thermal don't make sense because you are not using electricity to light the match. Radiant and nuclear is not right because you are not using nuclear energy to light the match. Nuclear and kinetic isn't right because you are using kinetic and you are not using nuclear energy.
Answer:
answer is B. thermal and radiant
Explanation:
just got it right on edge
a 50.0kg skydiver experience a 740newton air resistance force determine her acceleration please help asap
Answer:
a = - 5 [m/s²].
Explanation:
To solve this problem we must use Newton's second law, which tells us that the sum of forces on a body is equal to the product of mass by acceleration.
∑F = m*a
where:
F = resultant force [N] (units of Newtons)
m = mass = 50 [kg]
a = acceleration = 9.81 [m/s²]
For this particular problem, the only forces acting are the force of gravity acting down with negative sign, while the force of air opposes the fall, in this way it is positive.
[tex]f_{air}-F_{grav}=-m*a[/tex]
As the movement is pointing down the acceleration will be taken as negative.
[tex]740-(50*9.81)=-50*a\\740-490.5 = -50*a\\249.5 = -50*a\\a = - 5 [m/s^{2} ][/tex]
We should note that in this case, the acceleration has a negative sign, this means that the force of the air makes the skydiver move upwards
What do we know about the relative strength of the electric field around each object?
Answer:
A charged object in an electric field experiences a force due to the field. The electric field strength, E, at a point in the field is defined as the force per unit charge on a positive test charge placed at that point.
Explanation:
A researcher changes the DNA in a soybean plant so that it produces offspring with a resistance to weed killer. Which best describes this scenario? genetic engineering gene therapy cloning selective breeding
Answer:
Genetic engineering
Explanation:
Genetic engineering or also called genetic modification is the direct manipulation of an organism's genome in order to bring about a desirable trait in such organism. In genetic engineering procedure, the organism manipulated is called TRANSGENIC or GENETICALLY MODIFIED (GM) organisms.
In this case, a researcher is said to change the DNA (genetic material) in a soybean plant so that it produces offspring with a resistance to weed killer. This describes a genetic engineering procedure in which the soybean plant is manipulated to yield a desired trait, which is resistance to weed killer.
Answer:
A. genetic engineering
Explanation:
I took the quiz
a car travels 200km in 3.0 hours. Determine the average velocity of the car
Answer:
66.67 km/hrExplanation:
The average velocity of the car can be found by using the formula
[tex]a = \frac{d}{t } \\ [/tex]
d is the distance
t is the time taken
From the question we have
[tex]a = \frac{200}{3} \\ = 66.66666...[/tex]
We have the final answer as
66.67 km/hrHope this helps you