A variable is a letter that stands in for a number and unit... True or False?
importance of estimation in our lives
Why do scientists not use US customary units when reporting their data?
One of the scientist's jobs is to report the results of his experiments to all the other scientists in the world.
There isn't a single real science shop anywhere in the world that uses the US customary system of units. Not one.
Even in the measly three countries that use it for measuring carpet, pumping gas, and weighing fish ... Myanmar, Liberia, an the USA ... the scientists do their work in the SI/MKS/metric system.
how do u calculate the kinetic energy of a ball of mass 0.25kg being kicked vertically upwards with a speed of 5m/s
Answer:
3.125J
Explanation:
K.E.= 1/2(mass)(velocity)^2
K.E.=1/2(0.25)(5)^2=3.125
The sky is blue because: Select one: a. the index of refraction for air is slightly larger for blue than for red b. atomic hydrogen is blue c. air molecules tend to polarize light along a horizontal axis d. oxygen and nitrogen molecules are small compared to the wavelengths of visible light e. oxygen molecules have a lower energy ground state than nitrogen molecules
Answer:
a. the index of refraction for air is slightly larger for blue than for red
an electron is moving at 3.6 x 10^3 m/s. a photon with what wavelength would have the same momentum????
Answer:
The wavelength of the photon that would have the same momentum as the electron is 202.2180996 nm
Explanation:
The velocity of the electron, v = 3.6 × 10³ m/s
The momentum of an electron, [tex]p_e[/tex] = m × v
Where;
v = The mass of the electron = 9.109 × 10⁻³¹ kg
∴ [tex]p_e[/tex] = 9.109 × 10⁻³¹ kg × 3.6 × 10³ m/s = 3.27924 × 10⁻²⁷ kg·m/s
According to the de Broglie equation, the momentum of a photon, p, is given as follows;
p = h/λ
Where;
h = 6.63 × 10⁻³⁴ J·s
λ = The wavelength of the photon
∴ λ = h/p
According to the question, we have;
p = [tex]p_e[/tex] = 3.27924 × 10⁻²⁷ kg·m/s
∴ λ = 6.63 × 10⁻³⁴ J·s/(3.27924 × 10⁻²⁷ kg·m/s) = 2.02180993 × 10⁻⁷ m
The wavelength of the photon, λ = 2.02180993 × 10⁻⁷ m = 202.2180993 × 10⁻⁹ m = 202.2180993 nm.
please help urgent have you ever seen the old “Pull the tablecloth out from under the dishes” trick? Use Newton’s 1st Law to explain the following:
a. In this trick, are the dishes “objects in motion,” or “objects at rest?”
b. If the dishes end up staying on the table, was an UNBALANCED FORCE applied to them? How do you know?
Answer:
I kinda dont remember the 1st law so search it up on
and it should tell u , but if u need any help from the
help me please i will mark as brainliest
Answer:
you would be paying $1845.26
A car has a mass of 2000 kg. While it is traveling along a perfectly flat road, it goes around an unbanked turn that has a radius of 40.0 m. The coefficient of static friction between the car tires and the road is 0.500. The car travels successfully around the turn at a constant speed of 10.0 m/s. Calculate the magnitude of the car's acceleration as it goes around the turn. _______ m/s^2
Answer:
2.5 m/s²
Explanation:
The given parameters are;
The mass of the car, m = 2,000 kg
The radius of the car, r = 40.0 m
The coefficient of friction between the car tires and the road, μ = 0.500
The constant speed with which the car moves, v = 10.0 m/s
The normal reaction of the road on the car, N = The weight of the car;
∴ N = m × g
Where;
g = The acceleration due to gravity ≈ 9.81 m/s²
N ≈ 2,000 kg × 9.81 m/s² = 19,620 N
The frictional force, [tex]F_f[/tex] = μ × N
The centripetal force, [tex]F_c[/tex] = m·v²/r
The car moves without slipping when [tex]F_f[/tex] = [tex]F_c[/tex]
Therefore, [tex]F_f[/tex] = 0.500 × 19,620 N = 2,000 kg × [tex]v_{max}[/tex]²/40.0 m
∴ [tex]v_{max}[/tex] = √(0.500 × 19,620 N × 40.0 m/2,000 kg) ≈ 14.007 m/s
Therefore, the velocity with which the car moves, v < [tex]v_{max}[/tex]
The cars centripetal acceleration, [tex]a_c[/tex] = v²/r
∴ [tex]a_c[/tex] = (10.0 m/s)²/40.0 m = 2.5 m/s²
The cars centripetal acceleration as it goes round the turn, [tex]a_c[/tex] = 2.5 m/s².
A glass rod acquires charge by rubbing silk cloth. The charge on the glass is due to:
(a) Friction
(b) Conduction
(c) Induction
(d) Radiation
Answer:
(a)Friction
Explanation:
It is due to friction as you are rubbing the glass rod with silk cloth
as friction occurs when 2 surfaces are rubbed against each other
Therefore it is charging by friction
what do you mean by scattering of light
Answer:
Scattering of light is the phenomenon in which light rays get deviated from its straight path on striking an obstacle like dust or gas molecules, water vapours etc. Scattering of light gives rise to many spectacular phenomena such as Tyndall effect and the “red hues of sunrise and sunset”.
A particular electric car is supplied with 300 kJ of chemical energy by the battery. Of this, a total of 70.5 kJ of energy is wasted as heat.
Calculate the overall efficiency of the electric car.
Supplied energy=300kJ
Wasted energy=70.5JUsed energy:-
[tex]\\ \sf\longmapsto 300-70.5=229.5kJ[/tex]
We know
[tex]\boxed{\sf Efficiency=\dfrac{Used\:Energy}{Supplied\:Energy}\times 100}[/tex]
[tex]\\ \sf\longmapsto Efficiency=\dfrac{229.5}{300}\times 100[/tex]
[tex]\\ \sf\longmapsto Efficiency=\dfrac{229.5}{3}[/tex]
[tex]\\ \sf\longmapsto Efficiency=76.5\%[/tex]
The overall efficiency of the electric car = 76.5 %
To find the efficiency the given values are:
Energy supplied = 300 kJ
Energy wasted = 70.5 kJ
Define efficiency and calculate the value of efficiency.In the system the output energy is compared to the input energy is known as efficiency. That can be written as percentage ratio of output energy to the input energy.
Formula of efficiency is,
Efficiency = ( E out / E in ) × 100
Here, Energy supplied = 300 kJ
so, energy used = Energy supplied - Energy wasted
= 300 - 70.5
= 229.5 kJ
Thus, substituting E out = 300 kJ , E in = 229.5 kJ
Efficiency = ( 229.5 / 300 ) ×100
= 229.5 / 3
= 76.5
Hence, The overall efficiency of the electric car is 76.5 %
Learn more about efficiency,
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In----- theory, the actual wishes that are threatening to the dreamers conscious awareness are disguised
Answer:
Unconscious wish fulfillment
Explanation:
Unconscious wish fulfillment
(In the unconscious wish fulfillment theory, the actual wishes of the dreamer that are threatening to the dreamer's conscious awareness are disguised.)
can someone please help me with a and b? what do they mean by amplitude?
Explanation:
first answer is that the to and fro movement of a pendulum is known as amplitude
7) A ball is thrown upward at an initial velocity of 8.2 m/s, from a height of 1.8 meters above the ground. The height of the ball h, in metres can be represented, after t seconds, is modelled by the equation h = –4.8t² + 8.2t + 1.8. (a) Determine the height of the ball after 1.7 seconds.
Answer:
8392
Explanation:
d=s/t
A object of mass 200kg is pushed from rest by a force of 500N along a horizontal plane for 5.0 seconds. Calculate the acceleration of the object
Answer:
force=mass×acceleration
hence
acceleration is given by force÷mass
(500÷200)*5=12.5
Which type of reactions usually happens slowest?
Answer:
option b is correct..................
4. When setting goals, you should do everything EXCEPT which of the following?
Take into account your current level of activity.
Ask all of your friends what they think your goals should be..
Set a time limit.
Be realistic.
An object moving north with an initial velocity of 14 m/s accelerates 5 m/s2 for 20 seconds. What is the final velocity of the object?
39 m/s
90 m/s
114 m/s
414 m/s
Answer:
option C
Explanation:
Final velocity of the object is 114 m / s. Hence, final velocity of the object is 114 m / s.
A sound frequency 100Hz and wavelength 3.34m is travelling through air, calculate the Velocity of sound in air.
Answer:
334m/s
Explanation:
If you take the data you gave and insert it into the equation f=v/λ the frequency would come out to be 3.34m
334 m/s is the Velocity of sound in air.
What is the velocity of a wave?Wave velocity in common usage refers to speed, although, properly, velocity implies both speed and direction.
The velocity of a wave is equal to the product of its wavelength and frequency (number of vibrations per second) and is independent of its intensity.
Mathematically , v=fλ
According to the question,
Sound frequency (f) = 100Hz
Wavelength (λ)= 3.34m
Computing the values in the formula,
v=fλ
v = 100Hz x 3.34m
v= 334m/s
Therefore,
Velocity of sound in air is 334 m/s.
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A cyclist goes round a circular path of circumference 343 m in s. The angle made by him, with the vertical is
WITH STEPS PLZ
you need the number of seconds to calculate the distance. I'm assuming that the seconds were written in the question but you forgot to write the here, you can calculate the distance then and find the exact point where the cyclist stopped since you have the circumference. then you can find the angle (after finding the distance he cycled) by subtracting it from 360 since the circular path will have an angle of 360 degrees.
Although your question lacks some data A general answer is provided :
The angle made vertically = 360° - x°
where x = angle at which the the cyclist stopped
and circumference of the circular path = Total Distance travelled by the cyclist
First step : determine the distance travelled by the cyclist vertically
circumference = 2*π*r
343 = 2*π * r
∴ r = 343 / ( 2π ) = 54.59
therefore distance travelled by the cyclist vertically = 54.59 * 2 = 109.18 m
Given that the time travelled is missing
assuming the angle to the distance travelled by the cyclist before it stopped vertically = 360° - x°
This is because the Total angle of a circular path = 360°
Learn more about circular paths : https://brainly.com/question/24210487
Using your Periodic Table, which element below has the smallest atomic radius? A.) Sodium, B.) Chlorine, C.) Phosphorus, D.) Iron
Chlorine has the smallest atomic radius since the atomic radius decreases as you travel to the right and up
The velocity ratio of a pulley system is 4. What does it means
Answer:
Velocity ratio = distance travelled by effort / distance travelled by load. Which is equal to effort arm / load arm. When velocity ratio (VR) is 4, the effort arm is greater than load arm.
If 20N force produces an acceleration of 5ms^-2 In a body then the mass of the body will be:
A.4kg
B.5kg
C.1/4kg
D.1/5kg
Can someone pls help, thank you in advance!
What is an example of a force applied at an angle to displacement
Answer:
an object sliding down hill
Explanation:
On a slope, the force applied is due to gravity. Its direction is straight down. If the object is sliding down the hill, its displacement is at an angle to the applied force. The angle of displacement will depend on the steepness of the hill.
6.
For a given prism the angle of incidence is changed from 0° and 90', the angle of deviation [ ]
b) decreases
c) first decreases and then increases
d) first increases and then decreases
a) increases
Answer:
increase
Explanation:
please mark as brainlyest
Answer
A.Increses
Explanation:
A cricketer throws a ball sideways with an initial velocity of 30 m/s. She releases the ball from a height of 1.3m. Calculate how far the ball travels before hitting the ground.
Answer:
78.34
Explanation:
1.3/30=78.3m
Question in the picture please help me...
Show all steps please....
Answer: i)A to B : (ice) freezing
ii) B to C (water) boiling
C to D (steam) evaporating
explanation: 0° is the freezing point of water when temperature increases from 0° the water starts melting. As 100° is the boiling point of water so at 100° the water completely melts and it starts boiling during boiling water changes into steam(water vapour) and it evaporates
give one example where friction is a hindrance.
Answer:
an example of when friction is a hindrance, is if someone with shorts is sliding down a slide. their skin rubbing on the slide will cause friction and will slow them down. another example is if you're dragging a large wooden box across the floor. the wood and the floor interacting cause friction and will make it more difficult to push the box.
Explanation:
hope this helps :D
An oscillator completes 240 cycles in 5.2 minutes.
Calculate its period (in seconds) and frequency (in Hz).
Answer:
I. Period = 1.3 seconds
II. Frequency = 0.769 Hertz
Explanation:
Given the following data;
Number of oscillation = 240 cycles
Time = 5.2 minutes.
Conversion:
1 minute = 60 seconds
5.2 minutes = X seconds
X = 60 * 5.2
X = 312 seconds
To find the following;
I. Period
Mathematically, the number of oscillation of a pendulum is given by the formula;
[tex] Number \; of \; oscillation = \frac {Time}{Period} [/tex]
Making period the subject of formula, we have;
[tex] Period = \frac {Time}{Number \; of \; oscillation} [/tex]
Substituting into the formula, we have;
[tex] Period = \frac {312}{240} [/tex]
Period = 1.3 seconds
II. Frequency
[tex] Frequency = \frac {1}{Period} [/tex]
Substituting the values into the formula, we have;
[tex] Frequency = \frac {1}{1.3} [/tex]
Frequency = 0.769 Hertz
