A man walks 30 m to the west, then 5 m to the east in 45 seconds.
What is his average speed?
An elevator motor provides 45.0 kW of power while lifting an elevator 35.0 m. If the elevator contains seven passengers each with an average mass of 70.0 kg and it takes 20.0 s to accomplish this task, determine the mass of the elevator.
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
Easy question I’ll give extra points. Help
Answer:
the answer is A
I wish you a good day!
Answer:
THe answer is graph 2 as it represents the puck going in a linear motion
Explanation:
Although planets orbit the Sun in ellipses, all the planetary orbits are fairly close to circular and not very eccentric.
True
False
Answer:
False
Explanation:
The Sun rotates in this same, right-hand-rule direction. All planetary orbits lie in nearly the same plane. All planetary orbits are nearly circular (eccentricity near zero).
Rate as Brainliest please
Fill in the blanks using the following words: Solid, Liquids, Gasses, More, Less, Gas, Fluids, Higher, Lower, Sun, Radiation, Conductors
● Radiation transfers heat best through _________ because there is _______ space between the particles.
● Conduction transfers heat best through _______ because there is space between the particles.
● Convection transfers heat best through _______ which includes _______ and ______.
● Heat always moves from _________ temperature to _________ temperature.
● Heat from ______ travels to earth by ___________.
● Solids that transfer heat well ate known as _____________.
Answer:
Blank 1: Gasses
Blank 2: More
Blank 3: Solids
Blank 4: Fluids
Blank 5: Liquid
Blank 6: Gas
Blank 7: Higher
Blank 8: Lower
Blank 9: Sun
Blank 10: Radiation
Blank 11: Conductors
P.S. order of answers does not matter between Blank 5 and 6.
Hi please zoom in to see it clearly, uh you don’t have to answer them all but it would be nice !!! (no links please) :D
2) Which of the following is not a quality of a healthy relationship?
A) respect
B) trust
C) closed communication
D) honesty
A 2.5 Coulomb charge is placed in an electric field where it experiences an electrical force of 50.N. What is the value of the electrical field at the place where the charge is located?
Remember to identify all data (givens and unknowns), list equations used, show all your work, and include units and the proper number of significant digits to receive full credit. (5 points)
Answer: E= 20 N/C
Explanation: Charge q = 2.5 C , force F = 50 N. F = qE and
E= F/q= 50N / 2.5 C = 20 N/C
Which option identifies the specific knowledge that the team in the following scenario must possess?
A team of engineers is designing a space probe that will go to Saturn and collect atmospheric samples. The temperature and atmosphere on Saturn are much different from the conditions on Earth.
(A) The team must have a vast knowledge of thermodynamics.
(B) The team must have a vast knowledge of propulsion.
(C) The team must have a vast knowledge of fluid power systems.
(D) The team must have a vast knowledge of acoustics.
Answer:
The team must have a vast knowledge of thermodynamics
Explanation:
Just took the test!!!
Answer:
C. Thermodynamics
Explanation:
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?
Each minute, the disk completes 100 revolutions, so a point on the rim traverses a distance of 100 times the circumference of the disk and would have a linear speed of
100 rev/min
= (100 rev/min) × (2π × 50 cm/rev) × (1/100 m/cm) × (1/60 min/s)
= 5π/3 m/s ≈ 5.236 m/s
Then after 30 s of rotation, the point would have traveled a distance of
(5π/3 m/s) × (30 s) = 50π m ≈ 157.08 m
A tabletop two-slit interference experiment consists of a laser pointer shining through two narrow, closely spaced slits in an opaque barrier. The light from the slits produces a characteristic pattern of alternating bright and dark regions on a nearby wall. Listed are five ways to modify the parameters of the experiment. Match each modification according to the effect it would have on the spacing between the bright spots on the wall. In each case, assume that everything else is held constant.
a. Causes the spacing between the bright spots on the wall to increase.
b. Causes the spacing between the bright spots on the wall to decrease.
c. Has effed on the spacing between the bright spots on the wall.
1. increasing the distance d between the two slits in the barrier
2. increasing the brightness of the laser light
3. increasing the distance L from the slits to the wall
4. increasing the distance x from the laser to the slits
5. increasing the wavelength of the laser light
Answer:
a - 3, 5
b - 1
c - 2, 4
Explanation:
a). The distance between fringes on the screen
[tex]$y = \frac{m \lambda L}{d}$[/tex]
where, λ is wavelength, m is order of pattern, L is distance between slit and screen, d is separation between slits.
Now we analyze that spacing between bright spots increases as increasing distance L from slits to wall and increasing the wavelength of the laser light, λ.
b). The spacing between the bright spots decreases as the distance between the two slits increases.
c). Has no effect on the spacing between the bright spots on the wall by increasing the distance from the laser to the slits as well as increasing the brightness of the laser.
lus
A cup has a mass of 0.0650 kg and a
volume of 0.000250 m3, and is floating
in fresh water. Pennies are put into the
cup until the top of the cup is level with
the water line. What is the mass of the
pennies in the cup?
[?] kg
Pwater = 1,000 kg/m3
Answer:
hey but the person at the top is right
Answer:
0.185
Explanation:
Volume of water displaced = 0.000250 ( volume of cup )
Mass of water displaced by cup = density of water X volume of water displaced
= 1000 X 0.000250 = 0.250 kg
Mass of water displaced = mass of cup + mass of pennies ( law of flotation)
0.25 = 0.0650 + mass of pennies
Mass of pennies = 0.2500 - 0.0650
= 0.185 kg
Don’t hesitate to like and rate this answer. It would mean a lot for me.
Why is it imperative that the collision takes place in a plane parallel to the plane containing the camera lens
Answer:
It is imperative that the collision takes place in a plane parallel to the plane containing the camera lens so that parallax does not affects the recording of camera.
Explanation:
It is imperative that the collision takes place in a plane parallel to the plane containing the camera lens so that parallax does not affect the recording of the camera. There may occur an error in video analysis if the camera is tilted at an angle in relation to the collision plane.
(The role of the lens is to take light to a fixed focal point.)
NEED TO SUBMIT THIS IN 10 MINS, PLS HELP!!!!
Answer:
Your answer is B
because it's on sneel's law.
that is sin of incident ray / sin of refracted ray is refractive index
In a nuclear fusion reaction, atoms:
split apart.
combine.
explode.
cool down.
May you please help?
Choice-A is the main reason that people use the thing in the picture.
Acellus
What are harmful substances in the air,
soil, and water called?
A. pollutants
B. toxins
C. carcinogens
D. mutants
When you look at the backside of a shiny teaspoon held at arm's length, do you see yourself upright or upside down? (b) When you look at the other side of the spoon, do you see yourself upright or upside down? Assume in both cases that the distance between you and the spoon is greater than the focal length of the spoon.
Answer:
a) The back spoon gives a right image (upright)
b) the front gives an inverted image
Explanation:
The spoon is a curved metallic object, when we see ourselves from the back we have a convex mirror, in this type of mirror when the law of reflection is applied the rays diverge therefore the eye-brain system forms the image with the prolongation of the rays, therefore the image is straight and smaller than the object.
When we look through the deep side of the spoon, we have a concave mirror and as the object (we) is further away than the distance, the rays converge to a point, so the image is real, inverted smaller than the object.
In summary.
a) The back spoon gives a right image (upright)
b) the front gives an inverted image
HELP PLEASEEE it’s due soon
Answer:
254.982J
Explanation:
mass = 130kg
gravity = 9.807m/s^2
height = 0.200m
Answer:
potential energy = 254.8 jouleExplanation:
mass (m) = 130 kg
height (h) = 0.200 m
(g) = 9.8
potential energy = m×g×h
= 130×0.200×9.8
= 254.8 joule
A scientist measuring the resistivity of a new metal alloy left her ammeter in another lab, but she does have a magnetic field probe. So she creates a 4.5-m-long, 2.0-mm-diameter wire of the material, connects it to a 1.5 V battery, and measures a 3.0 mT magnetic field 1.0 mm from the surface of the wire. What is the material's resistivity
Answer:
[tex]3.49\times 10^{-8}\ \Omega\text{m}[/tex]
Explanation:
r = Radius = [tex]\dfrac{2}{2}=1\ \text{mm}[/tex]
B = Magnetic field = 3 mT
1 mm = Distance from the surface of the wire
V = Voltage
x = Distance from the probe = [tex]r+1=1+1=2\ \text{mm}[/tex]
R = Resistance
L = Length of wire = 4.5 m
Magnetic field is given by
[tex]B=\dfrac{\mu_0I}{2\pi x}\\\Rightarrow I=\dfrac{B2\pi x}{\mu_0}\\\Rightarrow I=\dfrac{3\times 10^{-3}\times 2\times \pi 2\times 10^{-3}}{4\pi 10^{-7}}\\\Rightarrow I=30\ \text{A}[/tex]
Voltage is given by
[tex]V=IR\\\Rightarrow R=\dfrac{V}{I}\\\Rightarrow R=\dfrac{1.5}{30}\\\Rightarrow R=0.05\ \Omega[/tex]
Resistivity is given by
[tex]\rho=\dfrac{RA}{L}\\\Rightarrow \rho=\dfrac{0.05\times \pi (1\times 10^{-3})^2}{4.5}\\\Rightarrow \rho=3.49\times 10^{-8}\ \Omega\text{m}[/tex]
The resistivity of the material is [tex]3.49\times 10^{-8}\ \Omega\text{m}[/tex].
When does a rubber band, which has been shot at a wall, have the most potential energy?
A When it is lying on the floor.
B When it is flying across the room.
C When it hits the wall.
D When it is stretched ready to shoot at the wall.
Answer:
C because that requires lots of energy
I WILL GIVE BRAINLIEST TO CORRECT ANSWER
Two boxes are being pulled to the right by a force F across a frictionless table. The force is acting directly on M 2 which is connected to M 1 by a massless cord. Which of the following expressions best represents the acceleration of M 1?
Telescopes are used for producing images, spectroscopy, and time monitoring of celestial objects.
True
False
Easy physics question help.!!!
Answer: This is not easy lol
Explanation:
A wave has a frequency of 67 Hz and a wavelength of 7.1 meters. What is the speed of this
wave?
Answer:
475.7 m/s
Explanation:
Given,
Frequency ( f ) = 67 Hz
Wavelength ( λ ) = 7.1 m
To find : Speed ( v ) = ?
Formula : -
v = f λ
v
= 67 x 7.1
= 475.7 m/s
Therefore,
the speed of the wave is 475.7 m/s.
WILL GIVE BRAINLIEST, ANSWER WITH ACTUAL ANSWER OR ELSE I WILL REPORT YOU!!!!!
Four students are assigned a project for which they must experimentally determine the coefficient of kinetic friction between a block of an unknown material and a table. Each student has their own idea of how to go about setting up the experiment. The group settles on two possible test to conduct: Student A's idea and Student B's idea. Student A believes the group can obtain the coefficient of kinetic friction by attaching a spring scale to the mass and pulling on the mass with the spring scale with a horizontally directed force. The reading on the spring scale at the moment the block begins to move is the coefficient of kinetic friction. Which of the following explains what is wrong with Student A's logic?
MC Options inserted in image below
Answer:
I know you said not to do this but I am doing a challenge and You asked this an hour ago. PLS DON'T REPORT ME.
Explanation: Sorry
A step-down transformer has 2500 turns on its primary and 5.0 x 10' tums on its secondary. If the potential difference across the primary is 4850 V, what is
the potential difference across the secondary?
Answer:
I dont know sorry
Explanation:
hehe
A fixed 14.1-cm-diameter wire coil is perpendicular to a magnetic field 0.52 T pointing up. In 0.28 s , the field is changed to 0.23 T pointing down. Part A What is the average induced emf in the coil
Answer:
the average induced emf in the coil is 0.016 V.
Explanation:
Given;
diameter of the wire, d = 14.1 cm = 0.141 m
change in magnetic filed strength, dB = 0.52 T - 0.23 T = 0.29 T
change in time, dt = 0.28 s
The area of the wire is calculated as follows;
[tex]A = \frac{\pi d^2}{4} \\\\A = \frac{\pi \times (0.141)^2}{4} \\\\A = 0.0156 \ m ^2[/tex]
The induced emf is calculated as follows;
[tex]emf = \frac{dBA}{dt} \\\\emf = \frac{0.29 \times 0.0156}{0.28} \\\\emf = 0.016 \ V[/tex]
Therefore, the average induced emf in the coil is 0.016 V.
A 4-foot spring measures 8 feet long after a mass weighing 8 pounds is attached to it. The medium through which the mass moves offers a damping force numerically equal to 2 times the instantaneous velocity. Find the equation of motion if the mass is initially released from the equilibrium position with a downward velocity of 7 ft/s. (Use g
Correct question is;
A 4-foot spring measures 8 feet long after a mass weighing 8 pounds is attached to it. The medium through which the mass moves offers a damping force numerically equal to √2 times the instantaneous velocity. Find the equation of motion if the mass is initially released from the equilibrium position with a downward velocity of 7 ft/s. (Use g = 32 ft/s²)
Answer:
x(t) = 7te^(-2t√2)
Explanation:
We are given;
Weight; W = 8 lbs
mass; m = W/g
g = 32 ft/s²
Thus;
m = 8/32
m = ¼ slugs
From Newton's second law we can write the equation as;
m(d²x/dt²) = -kx - β(dx/dt)
Rearranging this, we have;
(d²x/dt²) + (β/m)(dx/dt) + (k/m)x = 0
Where;
β is damping constant = √2
k is spring constant = W/s
Where s = 8ft - 4ft = 4ft
k = 8/4
k = 2
Thus,we now have;
(d²x/dt²) + (√2/(¼))(dx/dt) + (2/(¼))x = 0
>> (d²x/dt²) + (4√2)dx/dt + 8x = 0
The auxiliary equation of this is;
m² + (4√2)m + 8 = 0
Using quadratic formula, we have;
m1 = m2 = -2√2
The general solution will be gotten from;
x_t = c1•e^(mt) + c2•t•e^(mt)
Plugging in the relevant values gives;
x_t = c1•e^(mt) + c2•t•e^(mt)
At initial condition of t = 0, x_t = 0 and thus; c1 = 0
Also at initial condition of t = 0, x'(0) = 7 and thus;
Since c1 = 0, then c2 = 7
Thus,equation of motion is;
x(t) = 7te^(-2t√2)
2. Plastic is a great conductor of charge so it moves quicker.
True
False
Answer:
the answer is false
Explanation:
plastic doesnt conduct anything