A 56.6-kg crate rests on a level floor at a shipping dock. The coefficients of static and kinetic friction are 0.517 and 0.260, respectively. What horizontal pushing force is required to (a) just start the crate moving and (b) slide the crate across the dock at a constant speed
Answer:
Explanation:
Magnitude of frictional force = μ mg
μ is either static or kinetic friction.
To start the crate moving , static friction is calculated .
a ) To start crate moving , force required = μ mg where μ is coefficient of static friction .
force required =.517 x 56.6 x 9.8 = 286.76 N .
b ) to slide the crate across the dock at a constant speed , force required
= μ mg where μ is coefficient of kinetic friction , where μ is kinetic friction
= .26 x 56.6 x 9.8 = 144.21 N .
How to keep my family safe during a hurricane?
If you are not advised to evacuate or are unable to do so safely, stay indoors, away from windows, skylights and doors. Continue to monitor weather reports and do not go outside until the storm has passed. And, to protect your children from seeing too many sights and images of the hurricane, limit media exposure.
which of the two bodies a and b in the following graph is moving with higher speed and why
.........................................
pls say it fst its very urgent
A tennis ball hits with an initial velocity of 25 m/s [10 o above the
horizontal] starting from a height of 2.1 m, lands on the ground. There
is a net 15 m away and 0.9 m high. Will the ball clear the net at its
peak, and by how much?
First, calculate the components of its initial velocity v0:
v0x = v0cos10 = 24.6 m/s
v0y = v0sin10 = 4.34 m/s
The ball reaches its peak when vy = 0. Let's calculate the time it takes for vy to become zero:
vy = v0y - gt ---> t = v0y/g = 0.44 s
The horizontal distance it travels in this time is
x = v0xt = (24.6 m/s)(0.44 s)
= 10.8 m
Note that the net is 15 m away. After traveling a horizontal distance of 10.8 m, the height of the ball is
y = -(1/2)gt^2 + v0yt + 2.1
= -(4.9 m/s^2)(0.44 s)^2 + (4.34 m/s)(0.44 s) + 2.1 m
= -0.95 m + 1.9 m + 2.1 m
= 3.05 m
Note that this is the height of the ball at its peak. While the ball is well above the net at its peak, it is well short of its required horizontal distance to clear it. Instead, let's find the time it takes for the tennis ball to travel a horizontal distance of 15 m first:
x = v0xt ----> t = x/v0x = (15 m)/(24.6 m/s) = 0.61 s
Then calculate the height y when t = 0.61 s. If y > 0.9 m (height of the net), then the ball will clear the net.
y = -4.9t^2 + v0yt + 2.1
= -4.9(0.61 s)^2 + (4.34 m/s)(0.61 s) + 2.1 m
= -1.82 m + 2.65 m + 2.1 m
= 2.93 m
Yes, the ball will clear the net by 2.03 m.
The Keck Observatory is home to the largest Earth-based twin telescopes. The telescopes are located away from city lights, above the clouds where the atmosphere is clear, calm, and dry. In 1999, additional steps were taken to help the telescopes overcome any distortions caused by changes in the atmosphere by adding a laser sighting system. Now, the Keck telescopes can probe distant galaxies and capture images with more detail than even the Hubble Space Telescope. Scientists can now use the Keck telescopes to investigate many questions. What is one question the Keck telescopes would NOT help scientists answer
Answer:
Option D
Explanation:
The options for the question are
a) How do galaxies rotate?
b) What is the weather on Neptune?
c) What is the core of Saturn made of?
d) What other solar systems have planets?
Solution
The Hubble space telescope was designed and integrated into the extraterrestrial system in order to capture information about the surrounding universe. If the Keck Observatory has a better observation capacity than the Hubble space telescope then the scientist would be interested to know the surrounding planets in the solar system.
Hence, option D is correct
what is the size of the electron charge?
Answer:
It’s like medium uk
Explanation:
The size of electron charge is estimated to be 1.6 × 10-¹⁹
How do you find a wavelength?
What kind of waves are present during an earthquake?
a. Transverse
b. Longitudinal
c. Both transverse and longitudinal
Answer:
Explanation:
During an earthquake, there are both transverse and longitudinal wave. The answer is c.
Answer:
Explanation:
ans is c. Both transverse and longitudinal
_____ Rocks are porous.
A) Sedimentary
B) Metamorphic
C) igneous
Answer:
Sedimentary rocks are porous.
Explanation:
So option A) Sedimentary is your answer. Have a great summer
what is velocity Write its formula
Answer:
Explanation:
Determine the amount of work done by the applied force when a 87 N force is applied to move a 15 kg object a horizontal
distance of 4.5 meters at a constant speed.
Answer:
391.5 J
Explanation:
The amount of work done can be calculated using the formula:
W = F║d where the force is parallel to the displacementLooking at the formula, we can see that the mass of the object does not affect the work done on it.
Substitute the force applied and the displacement of the object into the equation.
W = (87 N)(4.5 m) W = 391.5 JThe amount of work done on the object is 391.5 J in order to move it 4.5 meters with an applied force of 87 Newtons.
Mass doesn't matter on amount of work done .We can calculate amount of work done through Force and Displacement
Force=87NDisplacement=4.5m[tex]\boxed{\sf W=Fd}[/tex]
W denotes to work doneF denotes to forced denotes to displacement[tex]\\ \sf\longmapsto Work\:Done=87(4.5)[/tex]
[tex]\\ \sf\longmapsto Work\:done=391.5J[/tex]
A student was asked to explain how a prism separates white light into its separate colors. The student explanation is below but contains a few mistakes that have been underlined. Re-write the student explanation and correct any errors that you find.
When a beam of white light enters a glass prism, the light waves increase in speed which causes them to bend and reflect inside the glass. White light is actually made up of a combination of different frequencies of light that bend at the same angle. When the light leaves the prism, it bends again, and it is separated into each different color and frequency forming a spectrum that looks like a rainbow.
Answer:
pp i hate khan academy pls help me
Suppose you have 10 helium-filled party balloons tied to a digital camera, so you can take photos of the core of a storm. With 10 balloons the camera will slowly but surely rise. As a storm approaches the atmospheric pressure drops. Assuming the air temperature and density are the same, the volume of each balloon will increase. When you let go, the speed of ascent will be
Answer:
a = 10 ρ_air g [tex]\frac{\Delta P}{m P_o}[/tex]
Explanation:
Let's solve this problem in parts, with the initial data the camera rises slowly, so we can assume that at constant speed, we apply the equilibrium condition
B - W = 0
The thrust is given by Archimedes' law
B = rho_aire g V_body
The volume of the body can be found from the ideal gas ratio
P V = n R T
let's use the subscript "o" for the initial concisions
V₀ = (nR) T₀/P₀ 1
we substitute
10 ρ_air g (nR) T₀ /P₀ = W
when the storm approaches the pressure decreases, P
If we use the ideal gas equation
V = (nR) T₀ / P
we combine this equation with equation 1
V = V₀P₀ / P
if we write the pressure
P = P₀ -ΔP
we substitute
V = [tex]\frac{V_oP_o}{P_o - \Delta P} =V_o \ ( 1 - \frac{\Delta P}{P_o} )^{-1}[/tex]
we expand serie and eliminate higher order terms
V = V₀ ([tex]1+ \frac{\Delta P}{Po}[/tex])
with this expression we can write the thrust
B = B₀ + ΔB
Newton's second law for the new conditions is
B - W = m a
(B₀ + ΔB) - W = ma
ΔB = m a
a = ΔB / m
a = 10 ρ_air g [tex]\frac{\Delta P}{m P_o}[/tex]
This is the initial acceleration of the camera
PLS SHOW WORK ON HOW YOU GOT IT PLS I BEG.
top ( 25 m ) | 75000 j | 0 j | 75000 j
-------------------|---------------|------------|-------------
bottom ( 0 ) | 0 j | 75000j | 75000 j
-------------------|---------------|------------|-------------
h d ( 12.5 m ) | 37500 j | 37500j | 75000 j
-------------------|---------------|------------|-------------
f d ( 5 m ) | 15000 j | 60000j | 75000 j
-------------------|---------------|------------|-------------
Suppose that scientists observe violent gas eruptions on a planet with an acceleration due to gravity of 3.9 m/s2. The jets throw sand and dust about 75 m above the surface. What is the speed i of the material just as it leaves the surface?
Answer:
The velocity with which the sand throw is 24.2 m/s.
Explanation:
acceleration due to gravity, a = 3.9 m/s2
height, h = 75 m
final velocity, v = 0
Let the initial velocity at the time of throw is u.
Use third equation of motion
[tex]v^{2} = u^{2} - 2 g h \\\\0 = u^{2} -2\times 3.9\times 75\\\\u=24.2m/s[/tex]
The velocity with which the sand throw is 24.2 m/s.
what is fire proof plastic
Explanation:
.Flame retar,dant plastic additi,ves are compounds added to plastics and other materials to inhibit, suppress or de,lay combustion. These compounds are useful in impending burning in the ign,ition phase of fire. They do not prevent char,ring or melting nor do they increase the heat resistance of a material
Science question, can someone please help ? I’ll give brainliest !!
Does a feather fall as fast as a rock in a vacuum? If so why?
Answer:
No.
Explanation:
A feather is less dense and thus less force exerted while a rock is very dense thus exerting more force .
Q:
The kinetic energy of an object can be determined
using the equation KE = 1/2mv^2, where ke is the
kinetic energy, m is the mass, and v is the speed of
the object. What is the mass of an object moving at
a speed of 12m/s that has 36 J of kinetic energy?
A:
0
2.0 kg
8.0 kg
0.13 kg
0.50 kg
Answer:
Explanation:
We will use the KE equation you wrote here and fill in what we are given:
[tex]36=\frac{1}{2}m(12)^2[/tex] and isolating the m:
[tex]m=\frac{2(36)}{12^2}[/tex] which gives us
m = .50 kg
Which two changes would decrease the gravitational force between two
objects?
A. Increase the distance between the objects.
B. Increase the mass of one of the objects.
C. Decrease the distance between the objects.
D. Decrease the mass of one of the objects.
E. Increase the mass of both objects.
Answer:
A. Increase the distance between the objects.
D. Decrease the mass of one of the objects.
Explanation:
The smaller the mass of an object the less gravity it has and the farther away two objects are the less gravitational force
A 15-watt bulb is connected to a circuit that has a total of 60. Ω of resistance. How many electrons are passing through that bulb every second?
Answer:
3.2075*10^16
Explanation:
Q=P/V just search up a converter and youll get 30V and so you do 15/30 which is a half and a single coulomb is 6.415*10^16 so you half it. I belive this is correct if you dont belive me wait for someone else smarter to answer and compare.
A truck hits a brick wall with a force of 100000 kg ms² the truck comes to a stop in 0.5 s what is the impulse
Answer:
Impulse = 50,000 J
Explanation:
Given: force = 100,000 kg ms^2 or N; time = 0.5 s
Unknown: impulse = ?
Equation: impulse = (force)(time)
Substitute: impulse = (100,000 kg ms^2 or N)(0.5 s)
Solution: impusle = 50,000 kg ms^2 or J
The equation provided (from the textbook) first defines the elastic potential energy of a spring as ΔUsp = −(WB + WW), where WB is work the spring does on an attached block and WW is work the spring does on the wall to which it is attached. But WW is ignored in the next step. Why?
Answer:
The given potential energy of the spring is expressed as follows;
ΔUsp = -(WB + WW)
Where;
WB = Th work done by the spring on the block to which it is attached
WW = The work done by the spring on the wall
We recall that work done, W = Force applied × Distance moved in the direction of the force
The work done by the spring on the block, WB = The spring force × The distance the block moves
The work done by the spring on the wall, WW = The spring force × The distance the wall moves
However, given that the wall does not move, we have;
The distance the wall moves = 0
∴ The work done by the spring on the wall, WW = The spring force × 0 = 0 J
Therefore, WW = 0 J, and the spring does not do work on the wall, and WW can be ignored in the next subsequent) steps
Explanation:
As a ball is released from 10ft above the ground, it falls freely (without friction)
toward the ground, at what point does the ball have the maximum gravitational
potential energy?
Can't be determined
At the top, at the release point.
Half
way
down the ground
At the floor
Answer:
Explanation:
The formula to find Potential Energy is PE = mgh, where m is the mass of the object, g is gravity, and h is the height from which the object can potentially fall. Because this is linear, then PE will increase as either the mass or the height increase (gravity is constant at 9.8 m/s/s). If the mass of the ball being dropped doesn't change, then the only thing that determines this ball's max PE is the height from which it is dropped; max PE ALWAYS occurs at the highest point from which an object can potentially fall. So your answer is "At the top".
Quanto tempo deve ficar ligado um ferro eletrico de 1000 w para que tenha o mesmo consumo de energia que um chuveiro de 4400 w que fica ligado 10 minutos
Answer:
Thus, the time for the first lamp is 44 minutes.
Explanation:
Power of first lamp, P' = 1000 W
Power of second lamp, P'' = 4400 W
time for second lamp, t'' = 10 minutes
Let the time for first lamp is t'.
As the energy is same, so,
P' x t' = P'' x t''
1000 x t' = 4400 x 10
t' = 44 minutes
The relationship between the decay constant (λ) and the half-life (t1⁄2) is given by the equation t(1/2) = 0.693/λ. Use the equation for N to derive this relationship.
Hint: when t = t(1/2), N/No = 0.5 (1 point)
A sample of carbon-14 initially consists of 5 × 1024 particles. Carbon-14 has a half-life of 5730 years.
a. What is the decay constant for carbon-14? (Answer in units of yr–1.) (1 point)
b. How many radioactive particles of the sample remain after 100 years? (1 point)
c. What percentage of the radioactive particles remains after 500 years? (1 point)
d. How many radioactive particles of the sample remain after 1000 years? (1 point)
e. How much time will it take for 50% of the particles to decay? (1 point)
f. How much time will it take for 99% of the particles to decay? (1 point)
g. How many half-lives will it take for 99% of the sample to decay? (1 point)
h. What is the initial decay rate of the sample? (Answer in decays/yr.) (1 point)
i. After 200 years, what is the decay rate of the sample? (1 point)
j. How long will it take for the decay rate to decrease to 1015 decays/year? (1 point)
k. How many half-lives have passed after the time you found in part (j)? (1 point)
Answer: A: 70/2=35
B: 35/2=17
C: 17.5/2=8.75
D: 8.75 of C-14 will be left
E: 5,730 years
F: 5,631
Explanation:
that’s all I got, hope I helped kinda
An extremely fast-moving charged particle traveling in a magnetic field can radiate X-rays, a phenomenon known as synchrotron radiation. Why is the magnetic field essential to this emission
Answer:
The magnetic field will help to create an electromagnetic radiation which will prevent the charged particle from moving in a constant direction in a straight path.
Explanation: A magnetic field is an area around a particle where magnetic energy is felt or experienced, this ensures that all the charged particle within the magnetic field will be influenced by magnet.
In the highlighted situation, the magnetic field will help to ensure that an electromagnetic radiation is created to synchrotron radiation occurs effectively.
In which stage of a star's life cycle, does gravity and fusion become balanced, and an adult star forms?
A. Main-sequence
B. Red supergiant
C. Protostar
D. White dwarf
Answer:
im guessing red giant-
name few biodegradable materials that get decomposed in a week
Answer:
Cardboard, Paper towels, Food waste, and wooden based items
Answer:
How fast do things biodegrade?
Vegetables 5 days –1 month
Aluminium cans 80–100 years
Glass bottles 1 million years
Styrofoam cup 500 years to forever
Plastic bags 500 years to forever
In a pinball machine, the launching spring with a spring constant of 30 N/m is compressed 0.15 m. How fast will it launch a 0.20 kg pinball?
Answer:
1.84 m/s
Explanation:
Applying,
The kinetic energy of the pinball = Elastic energy of the spring
mv²/2 = ke²/2
mv² = ke².................. Equation 1
Where m = mass of the pin ball, v = velocity of the pin ball, k = force constant of the spring, e = extension of the spring.
make v the subject of the equation
v = √(ke²/m)................ Equation 2
From the question,
Given: e = 0.15 m, k = 30 N/m, m = 0.20 kg
Substitute these values into equation 2
v = √[(30×0.15²)/0.2]
v = 1.84 m/s