Which best describes a reference frame?
Answer: A system or frame of reference are those conventions used by an observer (usually standing at a point on the ground) to be able to measure the position and other physical magnitudes.
Answer:
C a position from which something is observed
om edu 2021
Explanation:
Which statement is true about the SI System?
A-Uses different base units than the English measurement system.
B-Is used in scientific
measurement.
C-Includes the meter as its base unit for length.
D-All of the above.
Answer:
maybe the answer is in is D part
If a person has the values for an object's density and volume, what value can be calculated?
o the object's size
o the object's mass
the shape the object forms in a container
the amount of space the object takes up
Answer:
Answer:
The object's mass.
Explanation:
The formula d=m/v.
d --> density
m--> mass
v --> volume
With density and volume given, you can calculate the mass of the object.
Explanation:
What does Weber's Law about 'just noticeable differences' predict about how much someone has to change the brightness of a light before we can notice the difference? a. It depends on how bright the light was in the first place - the brighter it was, the less change is needed before we realize it. b. It depends on how long we have been looking at the light - the longer we have been looking, the more change is needed. c. It is always the same amount - 7 lux. d. It depends on how bright the light was in the first place - the brighter it was, the more change is needed before we realize it.
Answer:
answer A is the correct one
Explanation:
Weber's law states that "the smallest discernible change of a stimulus and proportional to the stimulus".
Applying this law to cases of optical intensity, the ratio must be
k = cte = ΔI / I
where ΔI is the variation of the intensity and I is the value of the intensity
In general, for humans, the constant is 0.15 for the rods and 0.015 for the cones of the retina.
When reviewing the answers, answer A is the correct one, since in order for the previous relationship to be maintained, the magnitudes must rise proportionally
Anuja hit a golf ball on a level field at 70 degrees and 40 degrees with the same total speed as shown below.
70°
40°
Which launch angle causes the ball to be in the air for the longest time?
o not enough information
40 degrees
70 degress
times are the same
Answer:
At 40 deg Vy = V sin 40
at 70 deg Vy = V sin 70
So the ball launched at 70 deg has the greatest vertical velocity and will remain in the air the longest:
Since t = Vy / g time for to reach zero vertical velocity and also the time for the ball to reach velocity Vy on the downward path
Mathis kicked a ball on a level surface at 30∘ and 60∘ with the same total speed as shown below.
Which launch angle results in the greater maximum height for the ball?
Answer: CORRECT (SELECTED)
60
blank refers to the method of spreading fertilizer evenly over the entire field by hand it is done at the blank stage
Answer:
Broadcasting is the method, not sure about the stage it is done in
Explanation:
Answer:
Broadcasting is the first (blank) second (blank) is Cultivation.
Explanation:
I took the test & got this answer correct.
A car rounds a banked curve as we will discuss in class on Tuesday. The radius of curvature of the road is R and the banking angle is θ. (a) In the absence of friction, what is the safe speed for the car to take this curve? (b) Now assume the coefficient of friction between the car’s tires and the road is µs. Determine the range of speeds the car can have without slipping up or down the road. (c) What is the minimum value of µs that makes the minimum speed zero? (d) If θ = 25.0 ◦ , for what values of µs can the curve be taken at any speed? Note: The upper limit of µs you will find is practically impossible to achieve for the car’s tires and the road.
Answer:
A) v = √[(rg(tan θ - µ_s))/(1 + (µ_s•tan θ))]
B)√[(rg(tan θ - µ_s))/(1 + (µ_s•tan θ))] ≤ v ≤ v = √[(rg(tan θ + µ_s))/(1 - (µ_s•tan θ))]
C) µ_s = tan θ
D) µ_s = 0.4663
Explanation:
A) The forces acting on the car will be;
Force due to friction; F_f
Force due to Gravity; F_g
Normal Force; F_n
Now, let us take the vertical direction to be j^ and the direction approaching the centre to be i^ downwards and parallel to the road surface by k^.
Also, we will assume that initially, F_n is in the negative k^ direction and that it will have a maximum possible value of; F_f = µ_s × F_n
Thus, sum of forces about the vertical j^ direction gives;
ΣF_j^ = F_n•cos θ − mg + F_f•sin θ = 0
Since F_f = µ_s × F_n ;
F_n•cos θ − mg + (µ_s × F_n × sin θ) =0
F_n = mg/[cos θ + (µ_s•sin θ)]
Also, sum of forces about the centre i^ direction gives;
ΣF_i^ = F_n(sin θ + (µ_s•cos θ)) = mv²/r
Plugging in formula for F_n gives;
ΣF_i^ = [mg/[cos θ + (µ_s•sin θ)]] × (sin θ + (µ_s•cos θ)) = mv²/r
Making v the subject gives;
v = √[(rg(tan θ - µ_s))/(1 + (µ_s•tan θ))]
B) What we got in a above is the minimum speed the car can have while going round the turn.
The maximum speed will be gotten by making the frictional force(F_f) to point in the positive k^ direction. This means that F_f will be negative.
Now, if we change the sign in front of F_f in the equation in part a that led to the minimum velocity, we will have the maximum as;
v = √[(rg(tan θ + µ_s))/(1 - (µ_s•tan θ))]
Thus the range is;
√[(rg(tan θ - µ_s))/(1 + (µ_s•tan θ))] ≤ v ≤ v = √[(rg(tan θ + µ_s))/(1 - (µ_s•tan θ))]
C) For the minimum speed to be 0, it implies that F_f will be in the negative k^ direction. Thus, Sum of the forces in the k^ direction gives;
ΣF_k^ = mg(sin θ - µ_s•cos θ) = 0
Thus;
mg(sin θ - µ_s•cos θ) = 0
Making µ_s the subject gives;
µ_s = sin θ/cos θ
µ_s = tan θ
D) If θ = 25.0°;
Thus;
µ_s = tan 25
µ_s = 0.4663
please help me. i have 2 hours
the missing word is clockwise moment. I hope this helps good luck
What is the net force required to give an automobile with a mass of 2,100 kg an acceleration of 5.4 m/s^2?
Answer:
Net force = 11340 N
Explanation:
Given that,
Mass of an automobile, m = 2100 kg
Acceleration of the automobile, a = 5.4 m/s²
We need to find the net force required for the automobile. The net force is the product of mass and acceleration. It can be given by the formula as follows :
[tex]F=ma\\\\F=2100\ kg\times 5.4\ m/s^2\\\\F=11340\ N[/tex]
So, the net force is 11340 N.
Because force is a vector measurement, it has both magnitude and
Before the development of quantum theory, Ernest Rutherford's experiments with gold atoms led him to propose the so-called Rutherford Model of atomic structure. The basic idea is that the nucleus of the atom is a very dense concentration of positive charge, and that negatively charged electrons orbit the nucleus in much the same manner as planets orbit a star. His experiments appeared to show that the average radius of an electron orbit around the gold nucleus must be about 10−1010−10 m. Stable gold has 79 protons and 118 neutrons in its nucleus.
What is the strength of the nucleus' electric field at the orbital radius of the electrons?
What is the kinetic energy of an electron in a circular orbit around the gold nucleus?
Answer:
a) F = -1.82 10⁻¹⁵ N, b) K = 9.1 10⁻¹⁶ J
Explanation:
a) To calculate the force between the nucleus and the electrons, let's use the Coulomb equation
F = k q Q / r²
as the nucleus occupies a very small volume compared to electrons, we can suppose it as punctual
let's calculate
F = 9 10⁹ (-1.6 10⁻¹⁹) (79 1.6 10⁻¹⁹) / (10⁻¹⁰)²
F = -1.82 10⁻¹⁵ N
b) they ask us for kinetic energy
let's use Newton's second law
F = m a
acceleration is centripetal
a = v² / r
we substitute
F = m v² / r
v = √ (F r / m)
v = √ (1.82 10⁻¹⁵ 10⁻¹⁰ / 9.1 10⁻³¹)
v = √ (0.2 10⁻¹⁶)
v = 0.447 10⁸ m / s
kinetic energy is
K = ½ m v²
K = ½ 9.1 10⁻³¹ (0.447 10⁸)²
K = 0.91 10⁻¹⁵ J
K = 9.1 10⁻¹⁶ J
what will happen if a low massive main sequence star runs out of hydrogen fuel?
Answer:
Low mass stars are: hydrogen burning in the core while on the Main Sequence. As the hydrogen fuel runs out, extreme pressure raises the temperature to 100 million degrees, where helium burning becomes possible.
when water in a brook or system of pipes flows from a wide region to a narrow region, the speed of water in the narrow region is
Answer:
more
hope this helps
plz mark brainliest
(HURRY I NEED HELP NOW ILL GIVE YOU BRILLIANT). Why do you think it's impossible for an element to appear on only one side of a valid
chemical equation? And I science
Answer:
i got you
Explanation:
Unfortunately, it is also an incomplete chemical equation. ... But if we count the number of oxygen atoms in the reactants and products, we find that there are two oxygen atoms in the reactants but only one oxygen atom in the products.
square root of 1024 using fractorization method
Answer:
= 32Explanation:
hope that will help youHelp pls it’s urgent
Answer:
A
Explanation:
Refraction
I don't understand why will only the 12 ohms lamps turn on when the switch is in position 2. shouldn't the current flow like this (like I highlighted in the picture)?
Explain why a ping pong ball and bouncy ball of the same size have different weights
Answer:
the material
Explanation:
weight is defined as the amount of force on the object because of gravity. ping pong balls and bouncy balls are made out of different materials that are different weights. most bouncy balls are also not hollow, unlike ping pong balls. these factors affect the weight of these objects.
Light refracts when traveling from air into glass because light
O A Travels at the same speed in air and in glass
B Frequency is greater in air than in glass
OC Frequency is greater in glass than in air
D Travels slower in glass than in air
Answer:
the last one
Explanation:
ii took the quiz and it was right... i think
In the International Space Station which orbits Earth, astronauts experience apparent weightlessness because:_________
a) the astronauts and the station are in free fall towards the center of the Earth.
b) there is no gravity in space. the station is kept in orbit by a centrifugal force that counteracts the Earth's gravity.
c) the station's high speed nullifies the effects of gravity.
d) the station is so far away from the center of the Earth.
Answer:
a) the astronauts and the station are in free fall towards the center of the Earth
Explanation:
Weightlessness is only a sensation of zero weight, a body experiences when it is in free fall towards the center of the Earth, caused by lack of contact force on such body.
Weightlessness doesn't mean the object has zero actual weight, is just a sensation of no weight due to lack of contact force to produce upward reaction on the object which gives the real sense of ones weight.
Thus, the astronauts experience apparent weightlessness because:
a) the astronauts and the station are in free fall towards the center of the Earth.
A 55-kg packing crate is pulled with constant speed across a rough floor with a rope that is at an angle of 40.0o above the horizontal. If the tension in the rope is 125 N, how much work is done on the crate to move it 5.0 m?
Answer:
478.75 J
Explanation:
W=force* displacement
constant speed= (a=0) net F=0
Horizontal component of tension
Tcosx
125Ncos40= 95.76 N
W= (95.76 N)(5 m)
=478.75 J
The work done in moving the crate across the given distance is 478.75 J.
The given parameters;
Mass of the packing create, m = 55 kgAngle of inclination of the rope, Ф = 40°Tension on the rope, T = 125 NDistance through which the crate is the moved, d = 5 mThe work done in moving the crate is the product of the horizontal component of the tension and the distance through which the crate is moved.
The work-done in moving the crate is calculated as;
W = Tcos(Ф) x d
W = 125cos(40) x 5
W = 478.75 J.
Thus, the work done in moving the crate across the given distance is 478.75 J.
Learn more here: https://brainly.com/question/19498865
Proposed Exercise: Work-Energy Theorem
In the situation illustrated in the figure below, a 365 pile hammer is used to bury a beam. The hammer is raised to a height of 3.0 (point 1) above the beam (point 2) and released from rest, sinking the beam of 7.4 (point 3). The rails exert on the hammer a constant friction force equal to 54 . Using the work-energy theorem, calculate (a) the speed of the hammer at the exact instant it reaches point 2 and (b) the mean force exerted by the hammer on the beam when moving it from position 2 to 3.
Tip: the force requested in item (b) is equal to the normal force that the beam exerts on
the hammer.
Answer:
152,000 N
Explanation:
(a) Initial potential energy = final kinetic energy
mgh = ½ mv²
v = √(2gh)
v = √(2 × 10 m/s² × 3.00 m)
v = 7.75 m/s
(b) Work done on pile hammer = change in energy
FΔy = 0 − (mgh + ½ mv²)
F (-0.074 m) = -((365 kg) (10 m/s²) (0.074 m) + ½ (365 kg) (7.75 m/s)²)
F (-0.074 m) = -11220.1 J
F ≈ 152,000 N
The displacement of an object moving 330 km North for 2 hours and an additional 220 km North for 5 hours is?
Answer:
Usbe
Explanation:
Temperature is a measure of
Answer:
The average kinetic energy
The amount of heat a substance has or the average kinetic energy of particles in a substance
what is power?
a- the magnitude of a force needed to move an object
b- how much work can be done in a given time
c- the distance over time that an object moves
d- the energy needed to create work
Answer:
b- how much work can be done in a given time
how much work can be done in a given time
A magician performs in a room with a ceiling, which is 2.70 m above his hands. He throws a ball upwards such that it reaches the ceiling with zero speed. Calculate the initial speed of the ball and the time it takes for it to reach the ceiling. A magician performs in a room with a ceiling, which is 2.70 m above his hands. He throws a ball upwards such that it reaches the ceiling with zero speed. Calculate the initial speed of the ball and the time it takes for it to reach the ceiling.
Answer:
a) v = 7.28 m/s
b) t = 0.74 s
Explanation:
a) The initial speed of the ball can be calculated using the following equation:
[tex] V_{f}^{2} = V_{0}^{2} - 2gh [/tex]
Where:
[tex]V_{f}[/tex] is the final speed = 0
[tex]V_{0}[/tex] is the initial speed =?
g: is the gravity = 9.81 m/s²
h: is the height = 2.70 m
[tex] V_{0} = \sqrt{2gh} = \sqrt{2*9.81 m/s^{2}*2.70 m} = 7.28 m/s [/tex]
Hence, the initial speed of the ball is 7.28 m/s.
b) To find the time that takes the balls to reach the ceiling we can use the next equation:
[tex] V_{f} = V_{0} - gt [/tex]
[tex] t = \frac{V_{0} - V_{f}}{g} = \frac{7.28 m/s}{9.81 m/s^{2}} = 0.74 s [/tex]
Therefore, the time it takes for the ball to reach the ceiling is 0.74 s.
I hope it helps you!
Which type of force occurs between two objects at a distance?
A. Applied force
B. Contact force
C. Non-contact force
D. Normal force
If your right you get 100 points & brainliest
Answer:
it has to be b contact forces
Explanation: because the two objects are next to each other but they still have force
Answer:
c
Explanation:
1
A truck increases its speed from 15 m/s to 60 m/s in 15 s. Its acceleration is
Why is a control group generally very important in an experiment?
Answer: The control group is the part where you see what happens when you change a variable you want to study/examine. Basically, you need the control group because you need something to see what happens when you change something.
Hope this Helps! :))))
A proton travels through uniform magnetic and electric fields. The magnetic field is in the negative x direction and has a magnitude of 3.54 mT. At one instant the velocity of the proton is in the positive y direction and has a magnitude of 2230 m/s. At that instant, what is the magnitude of the net force acting on the proton if the electric field is (a) in the positive z direction and has a magnitude of 5.25 V/m, (b) in the negative z direction and has a magnitude of 5.25 V/m, and (c) in the positive x direction and has a magnitude of 5.25 V/m
Answer:
(a). The magnitude of the net force is [tex](2.1\times10^{-18}\ N)k[/tex]
(b). The magnitude of the net force is [tex](4.23\times10^{-19}\ N)k[/tex]
(c). The magnitude of the net force is [tex](8.4\times10^{-19}\ N)i+(12.6\times10^{-19}\ N)k[/tex]
Explanation:
Given that,
Magnetic field [tex]B=-3.54\times10^{-3}i\ T[/tex]
Velocity = 2230j m/s
We know that,
The net force acting on the proton is equal to the sum of electric and magnetic force.
[tex]F=F_{e}+F_{B}[/tex]
(a). If the electric field is in the positive z direction and has a magnitude of 5.25 V/m,
We need to calculate the magnitude of the net force acting on the proton
Using formula of net force
[tex]F_{net}=e(E+v\times B)[/tex]
Put the value into the formula
[tex]F_{net}=1.6\times10^{-19}(5.25k+2230\times-3.54\times10^{-3}(j\times i))[/tex]
[tex]F_{net}=1.6\times10^{-19}(5.25k+2230\times-3.54\times10^{-3}(-k))[/tex]
[tex]F_{net}=(2.1\times10^{-18}\ N)k[/tex]
(b). If the electric field is in the negative z direction and has a magnitude of 5.25 V/m,
We need to calculate the magnitude of the net force acting on the proton
Using formula of net force
[tex]F_{net}=e(E+v\times B)[/tex]
Put the value into the formula
[tex]F_{net}=1.6\times10^{-19}(-5.25k+2230\times-3.54\times10^{-3}(j\times i))[/tex]
[tex]F_{net}=1.6\times10^{-19}(-5.25k+2230\times-3.54\times10^{-3}(-k))[/tex]
[tex]F_{net}=(4.23\times10^{-19}\ N)k[/tex]
(c). If the electric field is in the positive x direction and has a magnitude of 5.25 V/m
We need to calculate the magnitude of the net force acting on the proton
Using formula of net force
[tex]F_{net}=e(E+v\times B)[/tex]
Put the value into the formula
[tex]F_{net}=1.6\times10^{-19}(5.25i+2230\times-3.54\times10^{-3}(j\times i))[/tex]
[tex]F_{net}=(8.4\times10^{-19}\ N)i+(12.6\times10^{-19}\ N)k[/tex]
Hence, (a). The magnitude of the net force is [tex](2.1\times10^{-18}\ N)k[/tex]
(b). The magnitude of the net force is [tex](4.23\times10^{-19}\ N)k[/tex]
(c). The magnitude of the net force is [tex](8.4\times10^{-19}\ N)i+(12.6\times10^{-19}\ N)k[/tex]
