Find how much work ∆W is done by the motor in lifting the elevator:
P = ∆W / ∆t
where
• P = 45.0 kW = power provided by the motor
• ∆W = work done
• ∆t = 20.0 s = duration of time
Solve for ∆W :
∆W = P ∆t = (45.0 kW) (20.0 s) = 900 kJ
In other words, it requires 900 kJ of energy to lift the elevator and its passengers. The combined mass of the system is M = (m + 490.0) kg, where m is the mass of the elevator alone. Then
∆W = M g h
where
• g = 9.80 m/s² = acceleration due to gravity
• h = 35.0 m = distance covered by the elevator
Solve for M, then for m :
M = ∆W / (g h) = (900 kJ) / ((9.80 m/s²) (35.0 m)) ≈ 2623.91 kg
m = M - 490.0 kg ≈ 2133.91 kg ≈ 2130 kg
volcano has both useful and harmful effects give reason
Answer:
harmful effects
1. that will cause air pollution
2. that will destroy our earth
Answer:
useful effects of volcano are :-
it makes soil fertile it provides valuable nutrients for the soilharmful effects of volcano are:-
it makes air polluted it destroy the environment .hope it is helpful to you ☺️
A mass weighing 24 pounds, attached to the end of a spring, stretches it 4 inches. Initially, the mass is released from rest from a point 4 inches above the equilibrium position. Find the equation of motion. (Use g
Answer:
The equation of motion is [tex]x(t)=-[/tex][tex]\frac{1}{3} cos4\sqrt{6t}[/tex]
Explanation:
Lets calculate
The weight attached to the spring is 24 pounds
Acceleration due to gravity is [tex]32ft/s^2[/tex]
Assume x , is spring stretched length is ,4 inches
Converting the length inches into feet [tex]x=\frac{4}{12} =\frac{1}{3}feet[/tex]
The weight (W=mg) is balanced by restoring force ks at equilibrium position
mg=kx
[tex]W=kx[/tex] ⇒ [tex]k=\frac{W}{x}[/tex]
The spring constant , [tex]k=\frac{24}{1/3}[/tex]
= 72
If the mass is displaced from its equilibrium position by an amount x, then the differential equation is
[tex]m\frac{d^2x}{dt} +kx=0[/tex]
[tex]\frac{3}{4} \frac{d^2x}{dt} +72x=0[/tex]
[tex]\frac{d^2x}{dt} +96x=0[/tex]
Auxiliary equation is, [tex]m^2+96=0[/tex]
[tex]m=\sqrt{-96}[/tex]
=[tex]\frac{+}{} i4\sqrt{6}[/tex]
Thus , the solution is [tex]x(t)=c_1cos4\sqrt{6t}+c_2sin4\sqrt{6t}[/tex]
[tex]x'(t)=-4\sqrt{6c_1} sin4\sqrt{6t}+c_2[/tex] [tex]4\sqrt{6}[/tex] [tex]cos4\sqrt{6t}[/tex]
The mass is released from the rest x'(0) = 0
[tex]=-4\sqrt{6c_1} sin4\sqrt{6(0)}+c_2[/tex] [tex]4\sqrt{6}[/tex] [tex]cos4\sqrt{6(0)}[/tex] =0
[tex]c_2[/tex] [tex]4\sqrt{6} =0[/tex]
[tex]c_2=0[/tex]
Therefore , [tex]x(t)=c_1[/tex] [tex]cos 4\sqrt{6t}[/tex]
Since , the mass is released from the rest from 4 inches
[tex]x(0)= -4[/tex] inches
[tex]c_1 cos 4\sqrt{6(0)} =-\frac{4}{12}[/tex] feet
[tex]c_1=-\frac{1}{3}[/tex] feet
Therefore , the equation of motion is [tex]-\frac{1}{3} cos4\sqrt{6t}[/tex]
Audrey, an astronomer is searching for extra-solar planets using the technique of relativistic lensing. Though there are believed to be a very large number of planets that can be found this way, actually finding one takes time and luck; and finding one planet does not help at all with finding planets of other stars in the same part of the sky. Audrey is good at it, and finds one planet at a time, on average once every three months. a.) Find the expected value and
Answer:
- the expected value is 8
- the standard deviation is 2.8284
Explanation:
Given the data in the question;
The model N(t), the number of planets found up to time t, as a poisson process,
∴ N(t) has distribution of poisson distribution with parameter (λt)
so
the mean is;
λ = 1 every month = 1/3 per month
E[N(t)] = λt
E[N(t)] = (1/3)(24)
E[N(t)] = 8
Therefore, the expected value is 8
For poisson process, Variance and mean are the same,
Var[N(t)] = Var[N(24)]
Var[N(t)] = E[N(24)]
Var[N(t)] = 8
so the standard deviation will be;
σ[N(24)] = √(Var[N(t)] )
σ[N(24)] = √(8 )
σ[N(24)] = 2.8284
Therefore, the standard deviation is 2.8284
Which change will always result in an increase in the gravitational force between two objects?
O increasing the masses of the objects and increasing the distance between the objects
O decreasing the masses of the objects and decreasing the distance between the objects
O increasing the masses of the objects and decreasing the distance between the objects
• decreasing the masses of the objects and increasing the distance between the objects
Answer:
increasing the masses of the objects and decreasing the distance between the objects
Explanation:
A go-cart is traveling at 15 mi/hr. How long does it take the go-cart to travel 3 miles?
Answer:
12 min
Explanation:every 4 minutes is 1 mile
Will give brainliest!
Describe how heat is moving in the image and label each as Radiation, Conduction, or Convection.
Radiation / Conduction / Convection
Answer:
well in the pot there is conventional heat, the pot itself is giving off conductable heat, and the radiational heat is coming from the stove.
a disk of a radius 50 cm rotates at a constant rate of 100 rpm. what distance in meters will a point on the outside rim travel during 30 seconds of rotation?
Answer:
Wait lang po sandali po wait lang
It turns out that the depth in the ocean to which airborne electromagnetic signals can be detected grows with the wavelength. Therefore, the military got the idea of using very long wavelengths corresponding to about 30 Hz to communicate with submarines throughout the world. If we want to have an antenna that is about one-half wavelength long, how long would that be
Wavelength = speed / frequency.
Wavelength = 3x10^8 m/s / 30 hz
Wavelength = 10 million meters
1/2 wavelength = 5 million meters
(that's about 3,100 miles)
I'm pretty sure the frequency is wrong in the question.
I think it's actually 30 kHz, not 30 Hz.
That makes the antenna about 3.1 miles long.
You put a diode in a microelectronic circuit to protect the system in case an untrained person installs the battery backward. In the correct forward-bias situation, the current is 255 mA with a potential difference of 116 mV across the diode at room temperature (300 K). If the battery were reversed, so that the potential difference across the diode is still 116 mV but with the opposite sign, what would be the magnitude of the current in the diode
Answer:
The current in the new circuit is 0
Explanation:
A diode is an electronic component that allows the electric current to go only in one direction. If in the first case the current was 255 mA, and the battery was changed ( change in polarity ) no current will flow through the circuit. That change is similar or equivalent to change the diode to the no pass position
At which point is there the most potential energy? At which point is there the most kinetic energy?
A. Potential energy A; Kinetic energy B
B. Potential energy B; Kinetic energy D
C. Potential energy A; Kinetic energy D
D. Potential energy C; Kinetic energy D
Answer:
The cart mark (a) has the most potential energy and the cart marked (b) has the most kinetic energy
Chris used a non plane mirror to check out an box resting on a shelf. He wanted to find
the focal length of the mirror. The image of the box was located 15 cm behind the mirror
and the box was placed 19 cm from the mirror.
Chris used a non-plane mirror to check out a box resting on a shelf, the focal length of the mirror is mathematically given as
f=8.38cm
What is the focal length of the mirror?Question Parameter(s):
The image of the box was located 15 cm behind the mirror
and the box was placed 19 cm from the mirror.
Generally, the equation for the focal length is mathematically given as
1/f=1/u+1/v
Therefore
1/f=1/15+1/19
f=8.3823529cm
In conclusion, the focal length of the mirror
f=8.3823529cm
Read more about Lens
https://brainly.com/question/13161236
#SPJ2
The spaceship Enterprise 1 is moving directly away from earth at a velocity that an earth-based observer measures to be 0.62c. A sister ship, Enterprise 2, is ahead of Enterprise 1 and is also moving directly away from earth along the same line. The veolcity of Enterprise 2 relative to Enterprise 1 is 0.30c. What is the velocity of Enterprise 2
Answer:
The answer is "0.92 c"
Explanation:
[tex]v_1\ (earth) = 0.62 \ c \\\\v_2\ ( enterprise ) = -0.30[/tex]
so,
[tex]v_2 \ (earth) = 0.62 \ c - (-0.30 \ c) \\\\[/tex]
[tex]= 0.62 \ c +0.30 \ c\\\\= 0.92 \ c[/tex]
A dog runs 51 m west to fetch a ball and brings it back only 27 m before stopping.
The total displacement of the dog is:
The moment of inertia of the club head is a design consideration for a driver in golf. A larger moment of inertia about the vertical axis parallel to the club face provides more resistance to twisting of the club face for off-center hits. The mass of one club head is 200 g and its moment of inertia is 5000 g cm2 . What is the radius of gyration of this club head
Answer:
Explanation:
Moment of inertia I = M k² , where M is mass and k is radius of gyration .
Putting the given values in the equation
5000 = 200 x k²
k² = 25
k = 5 cm .
Radius of gyration is 5 cm .
a 7 kg object moving 10 m/s Right collides with a 14 kg object at rest. If after the collision the 7kg object is at rest and the 14 kg object is moving, what is the velocity of the 14 kg object after the collision?
Answer:
v2(final)=5 m/s
Explanation:
we are going to use the conservation of momentum here
m1*v1(initial)+m2*v2(initial)=m1*v1(final)+m2v2(final)
m1=7 kg v1(initial)=10 m/s
m2=14 kg v2(initial)=0 m/s (bc initially it is at rest)
v1(final)= 0 m/s (m1 stops moving after the collision)
v2(final)=?
7*10+14*0=7*0+14*v2(final)
70=14v2(final)
v2(final)=70/14 m/s=5 m/s
An 80.0-kg skydiver jumps out of a balloon at an altitude of 1,000 m and opens his parachute at an altitude of 200 m. A. Assuming the total friction (resistive) force on the skydiver is constant at 50.0 N with the parachute closed and constant at 3,600 N with the parachute open, find the speed of the skydiver when he lands on the ground. B. At what height should the parachute be opened so that the final speed of the skydiver when he hits the ground is 5.00 m/s
Answer:
[tex]24.9\ \text{m/s}[/tex]
[tex]206.7\ \text{m}[/tex]
Explanation:
m = Mass of skydiver = 80 kg
[tex]x_1[/tex] = Height for which the parachute is closed = 1000-200 = 800 m
[tex]x_2[/tex] = Height for which the parachute is open = 200 m
[tex]f_1[/tex] = Resistive force when parachute is closed = 50 N
[tex]f_2[/tex] = Resistive force when parachute is open = 3600 N
v = Velocity of skydiver on the ground
g = Acceleration due to gravity = [tex]9.81\ \text{m/s}^2[/tex]
h = Height from which the skydiver jumps = 1000 m
The energy balance of the system will be
[tex]mgh-f_1x_1-f_2x_2=\dfrac{1}{2}mv^2\\\Rightarrow 80\times 9.81\times 1000-50\times 800-3600\times 200=\dfrac{1}{2}\times 80\times v^2\\\Rightarrow v=\sqrt{\dfrac{2(80\times 9.81\times 1000-50\times 800-3600\times 200)}{80}}\\\Rightarrow v=24.9\ \text{m/s}[/tex]
The velocity fo the skydiver when he lands will be [tex]24.9\ \text{m/s}[/tex]
x = Height where the person opens the parachute
v = 5 m/s
[tex]mgh-f_1x_1-f_2x_2=\dfrac{1}{2}mv^2\\\Rightarrow 80\times 9.81\times 1000-50\times (1000-x)-3600\times x=\dfrac{1}{2}\times 80\times 5^2\\\Rightarrow 80\times 9.81\times 1000-50000+50x-3600x=\dfrac{1}{2}\times 80\times 5^2\\\Rightarrow x=\dfrac{80\times 9.81\times 1000-50000-\dfrac{1}{2}\times 80\times 5^2}{3550}\\\Rightarrow x=206.7\ \text{m}[/tex]
The height at which the parachute is to be opened is [tex]206.7\ \text{m}[/tex]
Which one the answer to this question
a lens with f = 50.0 cm is held 55.0 cm from an object. what is the image distance? (unit = cm)
Answer: 550 cm
Explanation:
Original equation: 1/f= 1/do + 1/di.
F=50.0 cm, and do=55.0.
Since we don't have di, we'll have to subtract do to the other side, making the equation: 1/f - 1/do= 1/di.
Doing the math, 1/f - 1/do is 0.0018181818
Then to get di by itself, you multiply both sides by di. Then you divide by 0.0018181818 to get di by itself. You then get: di= 1/0.0018181818
At that point, you just divide 1 by 0.0018181818, which will give you 550 cm
There could be simpler way, but that is just what I did to get the answer. Answer was right on Acellus
Which runner finished the 100 m race in the least amount of time?
Ming
Which runner stopped running for a few seconds during the race?
At what distance did Anastasia overtake Chloe in the race?
1: Ming
2: Chloe
3: 40m
I need help with this review question.
Answer:
The acceleration of the football is greatest
Explanation:
The more mass the more acceleration
An artificial satellite circling the Earth completes each orbit in 126 minutes. (a) Find the altitude of the satellite.
Answer:
Explanation:
Time period of rotation
T = 2πR/ V where R is radius of orbit and V is orbital velocity
Orbital velocity V = √ ( GM/R ) , m is mass of the earth .
T = 2πR √R / GM
T² = 4π²R³ / GM
Putting the values
( 126 x 60 )² = 4 x 3.14² x R³ / 6.67 x 10⁻¹¹ x 5.97 x 10²⁴
57.15 x 10⁶ = 39.44 x R³ / 39.82 x 10¹³
R³ = 577 X 10¹⁸
R = 8.325 x 10⁶ m
= 8325 km
Radius of earth = 6400 km
height of satellite = 8325- 6400 = 1925 km .
Question 7 of 11
>
A 1655 kg car drives down the highway. If the car has a momentum of 61250 kg. m/s, what is the velocity of the car?
Answer:
velocity = 37.01 m/s
Explanation:
momentum = mass * velocity
61250 = 1655 * x
x = 61250 / 1655
x = 37.0090634441
a 4.5 Hz wave has a wavelength of 0.8m. what is the speed
0.18 m/s
5.6m/s
5.3m/s
3.6m/s
Answer:
Explanation
g A thin-walled hollow cylinder and a solid cylinder, both have same mass 2.0 kg and radius 20 cm, start rolling down from rest at the top of an incline plane. The height of top of the incline plane is 1.2 m. Find translational speed of each cylinder upon reaching the bottom and determine which cylinder has the greatest translational speed upon reaching the bottom. Moment of inertia of hollow cylinder about its axis passing through the center is mr2 and for solid cylinder mr2/2
Answer:
a. i. 3.43 m/s ii. 2.8 m/s
b. The thin-walled cylinder
Explanation:
a. Find translational speed of each cylinder upon reaching the bottom
The potential energy change of each mass = total kinetic energy gain = translational kinetic energy + rotational kinetic energy
So, mgh = 1/2mv² + 1/2Iω² where m = mass of object = 2.0 kg, g =acceleration due to gravity = 9.8 m/s², h = height of incline = 1.2 m, v = translational velocity of object, I = moment of inertia of object and ω = angular speed = v/r where r = radius of object.
i. translational speed of thin-walled cylinder upon reaching the bottom
So, For the thin-walled cylinder, I = mr², we find its translational velocity, v
So, mgh = 1/2mv² + 1/2Iω²
mgh = 1/2mv² + 1/2(mr²)(v/r)²
mgh = 1/2mv² + 1/2mv²
mgh = mv²
v² = gh
v = √gh
v = √(9.8 m/s² × 1.2 m)
v = √(11.76 m²/s²)
v = 3.43 m/s
ii. translational speed of solid cylinder upon reaching the bottom
So, For the solid cylinder, I = mr²/2, we find its translational velocity, v'
So, mgh = 1/2mv'² + 1/2Iω²
mgh = 1/2mv² + 1/2(mr²/2)(v'/r)²
mgh = 1/2mv'² + mv'²
mgh = 3mv'²/2
v'² = 2gh/3
v' = √(2gh/3)
v' = √(2 × 9.8 m/s² × 1.2 m/3)
v' = √(23.52 m²/s²/3)
v' = √(7.84 m²/s²)
v' = 2.8 m/s
b. Determine which cylinder has the greatest translational speed upon reaching the bottom.
Since v = 3.43 m/s > v'= 2.8 m/s,
the thin-walled cylinder has the greatest translational speed upon reaching the bottom.
What is the unit of measurement of mass and weight?
Answer:
kilogram
In the International System of Units (SI), the kilogram is the basic unit of mass, and the newton is the basic unit of force. The non-SI kilogram-force is also a unit of force typically used in the measure of weight.
find the rms speed of a sample of oxygen at 30° C and having a molar mass of 16 g/mol.
At 30°C, the rms speed of a sample of oxygen with a molar mass of 16 g/mol is approximately 482.34 m/s.
The root mean square (rms) speed of a gas molecule is a measure of the average speed of the gas particles in a sample. It can be calculated using the formula:
vrms = √(3kT/m)
Where:
vrms is the rms speed
k is the Boltzmann constant (1.38 x 10^-23 J/K)
T is the temperature in Kelvin
m is the molar mass of the gas in kilograms
To calculate the rms speed of oxygen at 30°C (303 Kelvin) with a molar mass of 16 g/mol, we need to convert the molar mass to kilograms by dividing it by 1000:
m = 16 g/mol = 0.016 kg/mol
Substituting the values into the formula, we have:
vrms = √((3 * 1.38 x 10^-23 J/K * 303 K) / (0.016 kg/mol))
Calculating this expression yields the rms speed of the oxygen sample:
vrms ≈ 482.34 m/s
For such more questions on speed
https://brainly.com/question/31380575
#SPJ8
Easy question just don’t understand it please help.
Question 10 (10 points)
Listen
In an ionic solution, 5.0x1015 negative ions with charge -e pass to the right each
second while 8.0x1015 positive ions with charge +2e pass to the left. What are the
magnitude and direction (+ or -) of current in the solution? (to the right is the +
direction, to the left is the - direction)
Note: Your answer is assumed to be reduced to the highest power possible.
Your Answer:
x10
Answer
units
Answer:
Please I do not understand the instructions given at the end of the question
what is an example of vaporization?
Answer:
just search it up you'll get ur answer
does the stirling engine follow the law of conservation energy
Answer:
Conservation of Energy: Like all things, Stirling Engines follow the conservation of energy principle (all the energy input is accounted for in the output in one form or another). ... The hot one supplies all of the energy QH, while the cold one removes energy QC (a necessary part of the cycle).
Explanation:
Answer: Yes
Explanation: All the energy input is accounted for in the output in one form or another