what is meant by measurementwhat are the three requirements for selecting a unit of a physical quantity
Answer:
Three requirements for selecting a unit are
1. The unit should be reproducible.
2. It should be possible to define the unit without ambiguity.
3. The value of the unit should not change with space and time.
The block slides on a horizontal frictionless surface. The block has a mass of 1.0kg and is pushed 5.0N at 45°. What is the magnitude of the acceleration of the block?
Answer:
[tex]3.5\:\mathrm{m/s^2}[/tex]
Explanation:
Newton's 2nd law is given as [tex]\Sigma F = ma[/tex].
To find the acceleration in the horizontal direction, you need the horizontal component of the force being applied.
Using trigonometry to find the horizontal component of the force:
[tex]\cos 45^{\circ}=\frac{x}{5},\\\frac{\sqrt{2}}{{2}}=\frac{x}{5},\\x=\frac{5\sqrt{2}}{2}[/tex]
Use this horizontal component of the force to solve for for the acceleration of the object:
[tex]\frac{5\sqrt{2}}{2}=1.0\cdot a,\\a=\frac{5\sqrt{2}}{2}\approx \boxed{3.5\:\mathrm{m/s^2}}[/tex]
A Thomson's gazelle can run at very high speeds, but its acceleration is relatively modest. A reasonable model for the sprint of a gazelle assumes an acceleration of 4.2m/s2 for 6.5s , after which the gazelle CONTINUES at a steady speed.
a. What is the gazelles top speed?
b. A human would win a very short race with a gazelle. The best time for a 30 m sprint for a human runner is 3.6 s. How much time would the gazelle take for a 30 m race?
Answer:
The correct answer will be:
(a) 27.3 m/s
(b) 3.8 s
Explanation:
According to the question:
Acceleration,
[tex]a= 4.2 \ m/s^2[/tex]
Time,
[tex]t = 6.5 \ s[/tex]
(a)
The gazelles top speed will be:
⇒ [tex]V_{max} = at[/tex]
[tex]=4.2\times 6.5[/tex]
[tex]=27.3 \ m/s[/tex]
or,
[tex]= 27 \ m/s[/tex]
(b)
As we know,
s = 30 m
Now,
⇒ [tex]s = \frac{1}{2} at^2[/tex]
or,
⇒ [tex]t=\sqrt{\frac{2s}{a} }[/tex]
On putting the given values, we get
[tex]=\sqrt{\frac{2\times 30}{4.2} }[/tex]
[tex]=\sqrt{\frac{60}{4.2} }[/tex]
[tex]=3.78 \ s[/tex]
or,
[tex]=3.8 \ s[/tex]
An object is moving in a straight line at constant speed. A resultant torce begins to act upon
the object.
State the ways in which the force may change the motion of the object
Answer: The velocity magnitude or the velocity direction chages.
Explanation:
According to Newton's second law of motion, the acceleration of a system moved in same direction and is also directly proportional to the external force which acts on it while inversely proportional to the mass. The formula is: a = F/m
Based on the question, since the object obtains acceleration, then it can be infered that there will be changes in the velocity magnitude or the direction as a result of the motion.
With no friction, you can use the relationship between potential and kinetic energy to predict the speed of the car at the bottom of this hill from its starting height.
a. True
b. False
POSSIBLE POINTS: 4
A sound wave traveling through a solid material has a frequency of 5 hertz. The wavelength of the sound wave is 2 meters. What is the speed of sound in
the material?
50 m/s
1,000 m/s
.
25 m/s
10 m/s
17
18 19 20 21 22 23 24 25 26
19 20 21 2
Ne
12631
MAY
20
0
étv
Answer:
v = fy
speed is equal to frequency × wavelength
5 × 2
[tex]10m.s^{ - 1} [/tex]
True or False: It would be easier to run on a planet with high gravity than one with less gravity.
When two charged particles are moving toward each other, their velocities decrease until they eventually come to a
stop. What happens afterward? (1 point)
O They remain in the same place without moving.
O They accelerate toward each other.
O they bond and accelerate together.
O They accelerate in opposite directions.
When two charged particles are moving toward each other, they bond and accelerate together.
To find the correct statement among all the options, we need to know about electromagnetic force.
What is electromagnetic force?The force between any two dynamic charged particles is the electromagnetic force. It's a combination of electric force and magnetic force. What does happen, when two charged particles move towards each other?When two charged particles move towards each other, they combine with each other dur to the electromagnetic force. Then they are travelled together as a single particle along the direction of more acceleration.Thus, we can conclude that the option (C) is correct.
Learn more about electromagnetic force here:
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It takes 24 hours for _______?
a.Earth to circle the sun one time
b.earth to rotate on its axis one time
c. The sun to circle earth one time
d.the sun to rotate on its axis one time
Answer:
C
Explanation:
Earth rotates once in about 24 hours with respect to the Sun, but once every 23 hours, 56 minutes, and 4 seconds with respect to other, distant, stars. Earth's rotation is slowing slightly with time; thus, a day was shorter in the past. This is due to the tidal effects the Moon has on Earth's rotation.
Answer: the answer is b.
ps: the other answer is wrong, the earth rotates around the sun, and the sun doesn't rotate around the earth.
Explanation:
A tension of 35.0N is applied downward on a 2.50kg mass. What is the acceleration of the mass?
A. -59.5 m/s2
B. -14.0 m/s2
C. -4.20 m/s2
D. -23.8 m/s2
Answer:
D. -23.8 m/s2
Explanation:
Answer:
[tex]\text{B. }-14.0\:\mathrm{m/s^2}[/tex]
Explanation:
From Newton's 2nd Law, we have [tex]\Sigma F=ma[/tex].
Substituting given values, we get:
[tex]-35.0=2.50a,\\a=\frac{-35.0}{2.50},\\a=\boxed{-14.0\:\mathrm{m/s^2}}[/tex]
*Note the negative sign simply implies that the mass is travelling downwards (direction).
Four passengers with combined mass 250 kg compress the springs of a car with worn out shock absorbers by 4.00cm when they enter it. Model the care and passengers as a single body on a single ideal spring. If the loaded has a period of vibration of 1.08 s, what is the period of vibration of the empty car?
Answer:
The time period of the empty car will be "1.00 s".
Explanation:
The given values in the question will be:
Mass,
m = 250 kg
Loaded car's time period will be:
T = 1.08 s
Shock absorbers compression,
x = 4 cm
or,
= 0.04 m
Now,
Weight of passengers will be:
⇒ [tex]F=mg[/tex]
[tex]=250\times 9.8[/tex]
[tex]=2450 \ N[/tex]
The spring constant of shock absorbers will be:
⇒ [tex]k=\frac{F}{x}[/tex]
[tex]=\frac{2450}{0.04}[/tex]
[tex]=61.250 \ N/m[/tex]
As we know,
Time period, [tex]T = 2 \pi\sqrt{\frac{M}{k} }[/tex]
On substituting the values, we get
[tex]1.08=2\pi \sqrt{\frac{M}{61250} }[/tex]
[tex]\frac{M}{61250}=0.02955[/tex]
[tex]M=0.02955\times 61250[/tex]
[tex]=1809.6 \ kg[/tex] (Total mass of car as well as its passengers)
Now,
The mass of the empty car will be:
⇒ [tex]m'=M-m[/tex]
[tex]=1809.6-250[/tex]
[tex]=1559.6 \ kg[/tex]
hence,
The time period of empty car will be:
⇒ [tex]T'=2\pi\sqrt{\frac{m'}{k} }[/tex]
[tex]=2\pi\sqrt{\frac{1559.6}{61250} }[/tex]
[tex]=2\pi \sqrt{0.0254}[/tex]
[tex]=1.003 \ s[/tex]
or,
[tex]=1.00 \ s[/tex]
To measure the heat capacity of an object, all you usually have to do is put it in thermal contact with another object whose heat capacity you know. As an example, suppose that a chunk of metal is immersed in boiling water (100°C), then is quickly transferred into a Styrofoam cup containing 250 g of water at 20°C. After a minute or so, the temperature of the contents of the cup is 24°C. Assume that during this time no significant energy is transferred between the contents of the cup and the surroundings. The heat capacity of the cup itself is negligible.
What is the heat capacity of this chunk of metal?
Answer:
The answer is "[tex]55.05 \ \frac{J}{K}[/tex]"
Explanation:
Given value:
[tex]Q_m=4.184 \times 10^3 \ J\\T_0=100^{\circ}\\T_1=24^{\circ}[/tex]
Calculating the heat capacity of this chunk of metal:
Using formula:
[tex]C_m=\frac{Q_m}{T_0-T_1}\\[/tex]
[tex]=\frac{4.184 \times 10^3}{100 -24}\\\\=\frac{4.184 \times 10^3}{76}\\\\=55.05 \ \frac{J}{K}[/tex]
1. In order to change the speed of a wave, you must change something about the medium. T or F
2. Diffraction is the process in which waves spread out as they pass through an opening. T or F
3. The larger the opening a wave passes through, the more the wave will diffract. T or F
Answer:
1) False
As the frequency can be defined as the number of times wave formed per unit time or in other words the numbers of a combination of a crest and trough forms. So the frequncy of a sound wave depends upon the source producing sounds
2)False
Diffraction is the process in which a light wave bends when they pass through a specified medium such as water.
3)True
hope it helps
1. What kind of force is the force of gravity? (1 Point) contact force
non-contact force electromagnetic force imaginary force
Answer:
the answer is electromagnetic force because gravity is a force of attraction
3.6 Make innovative suggestions on how you could instill healthy environmental values
in communities.
You could hold rallies which attract a lot of people, they come and you discuss apon making the world a better place and how you want to shape the society.
The plane has just taken off and reached a height of 200 m when one of its wheels falls off.
The wheel has a mass of 300 kg.
What speed does it hit the ground with?
(Ignore air resistance.)
Give your answer to the nearest 0.1 m/s
Use g = 9.8 m/s2 for the acceleration due to gravity.
A
6.3 m/s
Answer: 63 m/s
Explanation: If wheel drops vertically, you can use
conservation of energy : Ep = Ek. mgh = ½mv^2 and
solve v = √(2gh ) = √ (2·9.81 m/s²·200 m) = 62.6 m/s.
NOTE: wheel has also horizontal speed which was not mentioned here.
If you make multiple measurements of your height, you are likely to find that the results vary by nearly half an inch in either direction due to measurement error and actual variations in height. You are slightly shorter in the evening, after gravity has compressed and reshaped your spine over the course of a day. One measurement of a man's height is 6 feet and 1 inch. Express his height in meters, using the appropriate number of significant figures.
Answer:
H = 1.85 m
Explanation:
First, we will convert the height completely into inches. 1 feet contains 12 inches in it. Therefore:
H = (6 feet)(12 inch/1 feet) + 1 inch
H = 73 inches
Now, we will convert this height from inches to meters. 1 inch is equivalent to 0.0254 m. Therefore:
H = (73 inches)(0.0254 m/1 inch)
H = 1.85 m
what are the advantages of having a roof with a lower thermal conductivity?
Which of the following two is correct
Less energy is needed to heat the house
The roof is a better insulator
The roof is less likely to leak
The rate of energy transfer by conduction is greater
Weather will have a greater effect on the temperature of the house
Answer:
less energy is needed to heat the house
the roof is a better insulator
The correct advantage of having a roof with a lower thermal conductivity is Less energy is needed to heat the house. The correct answer is option 1.
A roof with lower thermal conductivity acts as a better insulator, reducing heat transfer between the interior and exterior of the house. This means that during colder months, less heat escapes through the roof, requiring less energy to maintain a comfortable temperature indoors. Additionally, a roof with lower thermal conductivity will help regulate indoor temperatures more effectively, making it a better insulator against external weather conditions. It does not directly affect the likelihood of roof leaks or increase the rate of energy transfer by conduction. Option 1 is correct.
To know more about thermal conductivity, here
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--The complete Question is, What are the advantages of having a roof with a lower thermal conductivity?
Which of the following two is correct
1. Less energy is needed to heat the house
2. The roof is a better insulator
3. The roof is less likely to leak
4. The rate of energy transfer by conduction is greater
5. Weather will have a greater effect on the temperature of the house. --
Explain the difference between the speed of an Electromagnetic wave and its frequency?
Answer:
Electromagnetic waves differ in their wavelengths and frequencies. The higher the frequency of an electromagnetic wave, the greater its energy. The speed of an electromagnetic wave is the product of its wavelength and frequency, so a wave with a shorter wavelength has a higher frequency, and vice versa.
Explanation:
(1) Viewers of Star Trek hear of an antimatter drive on the Starship Enterprise. One possibility for such a futuristic energy source is to store antimatter charged particles in a vacuum chamber, circulating in a magnetic field, and then extract them as needed. Antimatter annihilates with normal matter, producing pure energy. What strength magnetic field is needed to hold antiprotons, moving at 5.0 x 10^7 m/s in a circular path 2.00 m in radius? Antiprotons have the same mass as protons but the opposite (negative) charge.
(2) Is this field strength obtainable with today’s technology or is it a futuristic possibility?
Solution :
The relationship between the strength of magnetic field and the radiusof a charged particle's path is obtained through Newton's second law, which is given by :
F = ma
F = qvB and [tex]$a=\frac{v^2}{r}$[/tex]
Substituting these values in the second law of Newton,
[tex]$qvB=\frac{mv^2}{r}$[/tex]
Now solving for B, we get:
[tex]$B = \frac{mv}{rq}$[/tex]
[tex]$=\frac{(1.67 \times 10^{-27})(5 \times 10^{7})}{2\times 1.6 \times 10^{-19}}$[/tex]
= 0.261 T
The field strength can be obtained by using the technology of today.
Description of a recent example of human trafficking that has displayed in your community
what is the acceleration of each body of mass 5kg rests on a frictionless table and is connected to a cable that passes over a pulley onto a hanging body of mass 10kg
Answer:
6.53 m/s²
Explanation:
Let m₁ = 5 kg and m₂ = 10 kg. The figure is attached and free body diagrams of the objects are also attached.
Both objects (m₁ and m₂) have the same magnitude of acceleration(a). Let g be the acceleration due to gravity = 9.8 m/s². Hence:
T = m₁a (1)
m₂g - T = m₂a (2)
substituting T = m₁a in equation 2:
m₂g - m₁a = m₂a
m₂a + m₁a = m₂g
a(m₁ + m₂) = m₂g
a = m₂g / (m₁ + m₂)
a = (10 kg * 9.8 m/s²) / (10 kg + 5 kg) = 6.53 m/s²
Both objects have an acceleration of 6.53 m/s²
A waterfall is an example of what energy conversion?
Answer:
most common energy transformations is the transformation between potential energy and kinetic energy. In waterfalls such as Niagara Falls, potential energy is transformed to kinetic energy. The water at the top of the falls has gravitational potential energy. As the water plunges, its velocity increases.
Explanation:
Hope this helps you
( I got this from transformation and conservation article)
Think about routine tasks that astronauts might need to do inside and outside a
spaceship. Choose several tasks, and describe the features the ship and spacesuits
should have to account for zero gravity as the astronaut completes the task. Use
Newton's laws of motion in your analysis..
from the NASA website, COPYRIGHT Jun 8, 2015
Lupus is a temporary disease that can be cured easily. True False
Answer:
falseeee
Explanation:
Which situation is contrary to Newton’s first law of motion?
An object at rest begins to move when an external force is applied.
A moving object has a constant velocity under the influence of balanced forces.
An object at rest stays at rest as long as unbalanced forces act on it.
A moving object slows down when an external force is applied.
Answer:
An object at rest stays at rest as long as unbalanced forces act on it.
Explanation:
Inertia can be defined as the tendency of an object or a body to continue in its state of motion or remain at rest unless acted upon by an external force.
In physics, Sir Isaac Newton's First Law of Motion is known as Law of Inertia and it states that, an object or a physical body in motion will continue in its state of motion at continuous velocity (the same speed and direction) or, if at rest, will remain at rest unless acted upon by an external force.
The inertia of a physical object such as a truck is greatly dependent or influenced by its mass; the higher the quantity of matter in a truck, the greater will be its tendency to continuously remain at rest.
Hence, the situation which is contrary to Newton’s first law of motion is that, an object at rest stays at rest as long as unbalanced forces act on it.
According to Newton’s first law of motion, an object at rest stays at rest as long as unbalanced forces do not act on it.
Answer:
yes it right
Explanation:
cat
which chareged particles contribute to electricity, magnetism, and light
Answer:
Explanation:charged particles create an electric force field. Moving charged particles create a magnetic force field. Accelerating charged particles produce changing electric and magnetic force fields which propagate as EM waves.
A fisherman notices that his boat is moving up and down periodically without any horizontal motion, owing to waves on the surface of the water. It takes a time of 2.10 s for the boat to travel from its highest point to its lowest, a total distance of 0.600 m . The fisherman sees that the wave crests are spaced a horizontal distance of 6.50 m apart.
Required:
a. How fast are the waves traveling?
b. What is the amplitude of each wave?
c. If the total vertical distance traveled by the boat were 0.30 m but the other data remained the same, how would the answers to parts (a) and (b) be affected?
Answer:
See Explanation
Explanation:
a) We know that;
v = λf
Where;
λ = wavelength of the wave
f = frequency of the wave
v = velocity of the wave
So;
T = 2 * 2.10 s = 4.2 s
Hence f = 1/4.2 s
f = 0.24 Hz
The wavelength = 6.5 m
Hence;
v = 6.5 m * 0.24 Hz
v = 1.56 m/s
b)The amplitude of the wave is;
A = 0.600 m/2 = 0.300 m
c) Since the wave speed does not depend on the amplitude of the wave then the answer in (a) above remains the same
Where d = 0.30 m
A = 0.30 m/2 = 0.15 m
A thin film of acetone (n=1.25) lies on the surface of a thick piece of water (n=1.30). White light shines down from air onto the thin layer of acetone. Destructive interference occurs for m=3 for a wavelength in air of 600 nm. What is the thickness of the thin film?
Answer:
Explanation:
The wave of light is being reflected two times while going from lower to higher refractive index mediums
So there will be phase reversal two times .
Condition of destructive index
2 μ t = ( 2m+1) λ / 2
Substituting the values
2 x 1.25 x t = ( 2 x 3 + 1 ) x 600nm / 2
2.5 t = 2100 nm
t = 840 nm .
When the velocity of a body increase with time, it's acceleration is ---------
positive
negative
Answer:
Negative
Explanation: