Answer:
Physical Changes :- The substance in which no new substance is formed are called physical changes.
The molecular composition of the substance are totally same.
For example :- Crushing a mineral into powder.
What is the name of the Egyptian sun god, usually depicted as a hawk-headed man with a solar disk and cobra on his head
Answer: Re-Horakhty
Explanation:
He has a human body and a falcon head, he has a crown in form of a disk with a cobra on his head. Ra-Horakhty was thought of as the god of the rising sun.
The force that the left team pulls with is 1000 N. If the right team's total mass is 300 kg and they accelerate by 1.2 m/s2, what is the force of resistance on the right team
Answer:
the force of resistance on the right team is 360 N
Explanation:
Given;
force of the left team, = 1000 N
total mass of the right team, m = 300 kg
acceleration of the right team, a = 1.2 m/s²
The force of resistance of the right team is calculated as;
Force = mass x acceleration
Force, F = 300 x 1.2
Force = 360 N
Therefore, the force of resistance on the right team is 360 N
(12 points) Analysis from the point where the block is released to the point where it reaches the maximum height i) Calculate the highest height reached by the block (or the largest distance travelled along the ramp.) ii) Calculate the work done by the gravitational force. iii) Calculate the work done by the normal force. iv) Calculate the work done by the friction force.
Answer:
i) a₁ = -g (sin θ + μ cos θ), x = v₀² / 2a₁
ii) W = mg L sin θ , iii) Wₙ = 0
iv) W = - μ m g L cos θ x
Explanation:
With a drawing this exercise would be clearer, I understand that you have a block on a ramp and it is subjected to some force that makes it rise, for example the tension created by a descending block.
The movement is that when the system is released, the tension forces are greater than the friction and the component of the weight and therefore the block rises up the ramp
At some point the tension must become zero, when the hanging block reaches the ground, as the block has a velocity it rises with a negative acceleration to a point and stops where the friction force and the weight component would be in equilibrium along the way. along the plane
i) Let's use Newton's second law
the reference system is with the x axis parallel to the ramp
Axis y
N - W cos θ = 0
X axis
T - W sin θ - fr = ma
the friction force is
fr = μ N
fr = μ mg cos θ
we substitute
T - m g sin sin θ - μ mg cos θ = m a
a = T / m - g (sin θ + μ cos θ)
With this acceleration we can find the height that the block reaches, this implies that at some point the tension becomes zero, possibly when a hanging block reaches the floor.
T = 0
a₁ = -g (sin θ + μ cos θ)
v² = v₀² - 2a1 x
v = 0 at the highest point
x = v₀² / 2a₁
ii) the work of the gravitational force is
W = F .d
W = mg sin θ L
iii) the work of the normal force
the force has 90º with respect to the displacement so cos 90 = 0
Wₙ = 0
iv) friction force work
friction force always opposes displacement
W = - fr d
W = - μ m g cos θ L
It was found that ice cream sales decrease significantly as the temperature outside decreases; a very strong relationship was found. What is the most likely correlation coefficient from this hypothetical study
Answer:
Value closest to 1
Explanation:
It is described from the scenario above that ice cream sales decreases as the outside temperature increases, hence showing a strong relationship between both variables (icream sales and temperature). The correlation Coefficient is a metric used in regression modeling to depict the strength of relationship between two variables, (The dependent and independent variables). Correlation Coefficient ranges from (-1 to +1). With values close to 1 or - 1. Also the positive and negative signs are used to show the type of relationship between the variables. If an increase in variable A leads to a decrease in variable B, then we have negative correlation (-) ; while an increase or decrease in both variables depicts a positive correlation. The most likely correlation Coefficient for the study above will be a positive value which is close to 1 since the relationship is described as strong.
A child who is swimming toward shore at 0.78 m/s sees shark and picks up his speed
to 1.89 m/s. He covers 17.5 m until he lands on shore. What was his acceleration?
Answer:
0.085m/s²
Explanation:
Use v²=v0²+2a(d)
solve for a
v²-v0²/2d=a
Plug in givens
1.89²-0.78²/2*17.5=a
Plug into calculator
a=0.085m/s²
What is the magnitude of the electric field at a point 0.0055 m from a 0.0025
C charge?
kg
Use E = and k=9.00 x 10 N.m²/C2.
O A. 7.4 x 1011 N
O B. 2.0 x 1010 N
O C. 4.1 x 10°N
OD. 7.9 x 1012 N
Answer:
Explanation:
The equation for the electric field is
[tex]E=\frac{kQ}{r^2}[/tex] so filling in:
[tex]E=\frac{9.00*10^9(.0025)}{(.0055)^2}[/tex] which in the end gives you
E = 7.4 × 10¹¹, choice A
a car is travelling at 36 km per hour if its velocity increases to 72 km per hour in 5 seconds then find the acceleration of car in SI unit
Answer:
36 km /h means 10 m/s. Increase in speed is 10m/s in 5 s . Acceleration is ( 10/5 ) = 2 m/s^ 2.
a= 2m/s²
Explanation:
U=36km/h
V=72km/h
T=5s
Conversion of Km to m and H to s
1km = 1000m
36km=36×1000 = 36000m
1H = 3600s
For U, 36000/3600
=10m/s
For V,
72km= 72×1000 =72000
72000/3600
20m/s
a=(V-U)/T
a=(20-10)/5
a= 10/5
a= 2m/s²
The search for black holes involves searching for The search for black holes involves searching for Group of answer choices single stars that emit large amounts of X-rays. a stellar core greater than 3 solar masses large spherical regions from which no light is detected. pulsars with periods less than one millisecond. pulsars that are orbited by planets.
Answer:
Large spherical regions from which no light is detected
Explanation:
A black hole is an object that has an extremely high density such that it possesses very powerful gravitational force that prevents the escape of all objects including light from it, and consumes nearby objects.
Due to the power of the gravitational force of a black hole, at the center, objects are infinitesimally compressed resulting in the inapplicability of the concept of space and time and the location is known as a singularity
Therefore, the search for black holes involves searching for large spherical regions from which no light is detected.
If voltage , V = 100 + 6 volt and current , I = 10+ 0.2 A , then find
percentage error in R.
Explanation:
As we know, resistance is the ratio of voltage used and current flowing through the circuit. So,
R = V/IBy error calculation
∆R/R = [(∆V/V)100] + [(∆I/I)100]V = 100 ± 6% V
I = 10 ± 0.2% A
∆R/R= (5/100)×100 + (0.2/10)×100
∆R/R=5+2=7%
So, percentage error in resistance (R) = ± 7%.Answer:
Percentage error of R is ±7%
Space weather is dominated by a stream of charged particles emanating from the sun's magnetic field, known as ______________.
Answer:
solar windExplanation:
This stream of particles emanating from sun's magnetic field is known as the solar wind.
The gas and particles come from the Sun's hot outer atmosphere, called the corona. These particles from the corona are charged with electricity.
The ability of a metal to react with air and water is a
property.
O chemical, physical, respectively
O physical, chemical, respectively
o physical, physical, respectively
O chemical, chemical, respectively
[tex]\bold{{Answer}}[/tex]
O physical, chemical, respectively
please buddy correct me if im wrong
The ability of a metal to react with air and water is a chemical, chemical, respectively property
What is a chemical change?A chemical change occur when the substance's composition is changed or when bonds are broken and new ones are forms a chemical change occur .
When a metal burn in air or react with air it form metal oxide and when metal react with water it forms oxides or hydroxides and release hydrogen gas . In both the cases change in composition is taking place . hence , bot are chemical reactions
correct answer is O chemical, chemical, respectively
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To overcome the problems that blur images and don't provide the best resolution from Earth, astronomers have started using flexible mirrors that change shape many times each second. This technique is called:
Answer:
adaptive optics
Explanation:
simple
A boat takes off from the dock at 2.5m/s and speeds up at 4.2m/s2 for 6.0 seconds how far has the boat traveled
Answer:
The answer is "91 m"
Explanation:
[tex]v_0 = 2.5 \ \frac{m}{s}\\\\a = 4.2\ \frac{m}{s^2}\\\\t = 6.0\ s\\\\\Delta x=?[/tex]
Using formula:
[tex]\Delta x = v_0 t +\frac{1}{2} at^2\\\\[/tex]
[tex]= 2.5 \times 6.0 +\frac{1}{2} \times 4.2 \times 6.0^2\\\\= 90.6\ m \approx 91\ m[/tex]
After landing the aeroplane's momentum becomes zero. Explain how
the law of conservation holds here.
Answer:
The law of momentum conservation can be stated as follows. For a collision occurring between object 1 and object 2 in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision.
What is the enthalpy change, AH, for this reaction? Show your work to receive full credit. URGENT PICTURE INCLUDED !!!
Answer:
150 kJ
Explanation:
Applying,
ΔH = Energy level of Product(E') - Energy level of reactant(E)
Where ΔH = enthalpy change, E' and E = energy level of the product and the reactant respectively
ΔH = E'-E............. Equation 1
From the diagram,
Given: E' = 200 kJ, E = 50 kJ
Substitute these values into equation 1
ΔH = 200-50
ΔH = 150 kJ
Hence the enthalpy change for the reaction is 150 kJ
While traveling north on an expressway, a car traveling 60 mph (miles per hour) slows down to 30 mph in 12 minutes due to traffic conditions
Answer:
acceleration = - 150 m/s^2
distance = 9 miles.
Explanation:
initial speed, u = 60 mph
time, t = 12minutes = 0.2 hour
final speed, v = 30 mph
Let the acceleration is a and the distance is s.
By the first equation of motion
v = u + at
30 = 60 + a x 0.2
a = - 150 m/s^2
Let the distance is s.
Use third equation of motion is
[tex]v^2 = u^2 + 2 a s \\\\30^2 = 60^2 + 2 \times 150\times s\\\\s = 9 miles[/tex]
A car's bumper is designed to withstand a 5.04-km/h (1.4-m/s) collision with an immovable object without damage to the body of the car. The bumper cushions the shock by absorbing the force over a distance. Calculate the magnitude of the average force on a bumper that collapses 0.255 m while bringing a 890-kg car to rest from an initial speed of 1.4 m/s.
Answer:
3420.39 N
Explanation:
Applying,
Fd = 1/2(mv²-mu²)................. Equation 1
Where F = force on the bumber, d = distance, m = mass of the car, v = final velocity, u = initial velocity.
make F the subject of the equation
F = (mv²-mu²)/2d............... Equation 2
From the question,
Given: m = 890 kg, v = 0 m/s (to rest), u = 1.4 m/s, d = 0.255 m
Substitute these values into equation 2
F = [(890×0²)-(890×1.4²)]/(2×0.255)
F = -1744.4/0.51
F = -3420.39 N
The negative sign denotes that the force in opposite direction to the motion of the car.
Two students with masses of 40kg and 32 kg are sitting 22 m apart. What is the gravitational force of attraction between them?
I get 1.76 x 10^-10 Newton.
That's 0.000 000 000 176 Newton
Which is about 0.000 000 000 635 ounce of force pulling them together.
That's why we never notice it.
Two identical metallic sphere having unequal opposite charges are are placed
distance of 0.05m apart in air.
After bringing them in contact
with each other, they are again placed at the same distance apart, now the force of repulsion between them is 0.108 N. Calculate the final charge on each of them.
Answer:
Let the initial charges be q1 and q2 respectively.
After they come in contact, the charges are rearranged such that they acquire same charge.
let us say that charge on each of them is Q.
They are again brought apart at a distance of 0.9 m. Hence, the force between them will be given as
F = kQ2 / r2
0.025 = (9×109 x Q2) / 0.92
Q2 = 0.025 x 0.92 / 9×109
Q = 1.5 x 10-6 C
Explanation:
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3.00 m^3 of water is at 20.0°C.
If you raise its temperature to
60.0°C, by how much will its
volume expand?
Water
B = 207•10-6 0-1
(Unit = m^3)
Answer:
[tex]\triangle V = 0.02484m^3[/tex]
Explanation:
Given
[tex]V_1 = 3.00m^3[/tex] --- initial volume
[tex]T_1 = 20.0^oC[/tex] --- initial temperature
[tex]T_2 = 60.0^oC[/tex] --- final temperature
[tex]\gamma = 207*10^{-6[/tex] --- coefficient of thermal expansion:
Required
The change in volume
To do this, we make use of cubic expansivity formula
[tex]\triangle V = \gamma * V_2 * (T_2 - T_1)[/tex]
So, we have:
[tex]\triangle V = 207 * 10^{-6} * 3.00 * (60.0 - 20.0)[/tex]
[tex]\triangle V = 207 * 10^{-6} * 3.00 * 40.0[/tex]
[tex]\triangle V = 0.02484m^3[/tex]
The volume will expand by [tex]0.02484m^3[/tex]
A bicycle and a car start their journey at the same time the cyclist reaches it's top speed of 10mls in 15 the car reaches a speed if 15 MLS in55 which has the greater acceleration the car or the bicycle
Complete question is;
A bicycle and a car start their journey at the same time the cyclist reaches it's top speed of 10m/s in 15 s, the car reaches a speed of 15 m/s in 55 s. which has the greater acceleration the car or the bicycle.
Answer:
The bicycle has the greater acceleration.
Explanation:
Cyclist reaches a top speed of 10m/s in 15 s.
Formula for acceleration here is;
a = v/t
a = 10/15
a = 0.67 m/s²
Car reaches a speed of 15 m/s in 55 s.
Thus;
a = 15/55
a = 0.27 m/s²
From the 2 acceleration values gotten, we can say that;
The bicycle has the greater acceleration.
What happens in a series circuit when more bulbs are added? (Example: I start out with a complete series circuit with 2 bulbs. Then I add in several more wires and several more bulbs & bulb holders. Now I have a complete series circuit with 5 bulbs).
Answer:
when we add elements in a series circuit the voltage across each element decreases
Explanation:
In a series circuit the current the whole circuit is the same, since there is only one path,
resistance is the sum of the resistance of each element
R_{eq} = ∑ R_i
if we write ohm's law
V = i R_{eq}
we substitute
V = i ∑ R_i
therefore the total voltage is
V = ∑ i R_i = ∑ V_i
With this expression we see that the voltage decreases as we place more elements in the series circuit.
Specifically when we fear two elements the voltage across each element is
V_i = V / 2
when we have 5 elements the voltage across each element is
V_i = V / 5
therefore when we add elements in a series circuit the voltage across each element decreases
rainfall occurs on the earth due to effect of gravity
Answer:
TrueBecause Gravity is the force of attraction between two objects, and Earth's gravity pulls matter downward, toward its center. It pulls precipitation down from clouds and pulls water downhill. Gravity also moves air and ocean water. ... Gravity pulls denser air and water downward, forcing less dense air and water to move upward.Carryonlearning
To leave the gravitational pull of the Earth, and explore other planets, satellites must have at least:
Answer:
To explore the other planets, the satellite must have the velocity more than the escape velocity.
Explanation:
The minimum velocity required by any object to escape from the earth gravitational pull is called the escape velocity.
The escape velocity for any planet depends on the mass of planet and radius of planet. It does not depends on the mass of object. The escape velocity is same for any mass for a particular planet.
So, to explore the other planets, the satellite must have the velocity more than the escape velocity.
Margy is trying to improve her cardio endurance by performing an exercise in which she alternates walking and running 100.0 m each. If Margy is walking at 1.4 m/s and accelerates at 0.20 m/s2 during
Complete question is;
Margy is trying to improve her cardio endurance by performing an exercise in which she alternates walking and running 100.0 m each. If Margy is walking at 1.4 m/s and accelerates at 0.20 m/s² during one of the running portions, what is her final velocity at the end of the 100.0 m? Round your answer to the nearest tenth.
Answer:
6.5 m/s
Explanation:
We are told that she is walking at 1.4 m/s and accelerates at 0.20 m/s².
Thus;
Initial velocity; u = 1.4 m/s
Acceleration; a = 0.2 m/s²
Distance; s = 100 m
From Newton's equation of motion, we know that;
v² = u² + 2as
Where v is final velocity.
Thus;
v² = 1.4² + 2(0.2 × 100)
v² = 41.96
v = √41.96
v ≈ 6.5 m/s
From laboratory measurements, we know that a particular spectral line formed by hydrogen appears at a wavelength of 121.6 nanometers (nm). The spectrum of a particular star shows the same hydrogen line appearing at a wavelength of 121.8 nm. What is the receding speed of the star? c = 3x10^5 km/s
Answer:
[tex]v=-4.93\times 10^{5}~m/s[/tex] [negative sign denotes that it is moving away]
Explanation:
Actual wavelength of hydrogen spectral lines, [tex]\lambda=121.6~nm[/tex]
Apparent wavelength of hydrogen spectral lines from a star, [tex]\lambda'=121.8~nm[/tex]
So, shift in wavelength:
[tex]\Delta \lambda=\lambda'-\lambda[/tex]
[tex]\Delta \lambda=121.8-121.6[/tex]
[tex]\Delta \lambda=0.2~nm[/tex]
Using Doppler's shift:
[tex]\frac{\Delta \lambda}{\lambda} =-\frac{v}{c}[/tex]
[tex]\frac{0.2}{121.6} =-\frac{v}{3\times 10^8}[/tex]
[tex]v=-4.93\times 10^{5}~m/s[/tex] [negative sign denotes that it is moving away]
If you are driving 90 km/hkm/h along a straight road and you look to the side for 2.8 ss , how far do you travel during this inattentive period
Answer:
Distance = 70 meters
Explanation:
Given the following data;
Speed = 90 km/h
Time = 2.8 seconds
Conversion:
90 km/h to meters per seconds = 90 * 1000/3600 = 90000/3600 = 25 m/s
To find the distance covered during this inattentive period;
Speed can be defined as distance covered per unit time. Speed is a scalar quantity and as such it has magnitude but no direction.
Mathematically, speed is given by the formula;
[tex]Speed = \frac{distance}{time}[/tex]
Making distance the subject of formula, we have;
[tex] Distance = speed * time [/tex]
Substituting into the above formula, we have;
[tex] Distance = 25 * 2.8 [/tex]
Distance = 70 meters
The boiling point of a substance is _72 degree Celsius. This temperature will be equivalent to Kelvin scale is-------.
Answer:
345 K
Explanation:
Temperature can be defined as a measure of the degree of coldness or hotness of a physical object.
Generally, it is measured with a thermometer and its units are Celsius (°C), Kelvin (K) and Fahrenheit (°F).
Given the following data;
Boiling point = 72°CTo convert the temperature in degree Celsius to Kelvin, we would use the following mathematical expression;
Kelvin = 273 + °C
Substituting into the formula, we have;
Kelvin = 273 + 72
Kelvin = 345 K
Therefore, the temperature of 72°C will be equivalent to 345 K on the Kelvin scale.
6. An object is fired from the gound at 275 m/s at an angle of 55° N of E.
a. How far away did the object first hit the ground?
b. what is the maximum height that the object reaches?
there u go fella hope u understood
What is the acceleration of a motorcycle that starts from rest and reaches a velocity of 24 m/s in 8.5 seconds?
Answer:
2.82 m/s²
Explanation:
[tex]v = u + at \\ 24 = 0 + a(8.5) \\ a = 2.82 \: ms {}^{ - 2} [/tex]
The acceleration of a motorcycle is 2.82 m/s^2.
What is acceleration?Acceleration is the rate at which speed and direction of velocity vary over time. A point or object going straight ahead is accelerated when it accelerates or decelerates.
Even if the speed is constant, motion on a circle accelerates because the direction is always shifting. Both effects contribute to the acceleration for all other motions.
Given that:
Initial velocity of the motor cycle: u = 0 m/s.
Final velocity of the motorcycle = 24 meter/second.
Time taken to reach this velocity = 8.5 second.
Hence, acceleration of the motor cycle = change in velocity/time interval
= ( final velocity - initial velocity)/time interval
= ( 24 m/s - 0 m/s)/8.5 s
= 2.82 m/s^2.
Its acceleration is 2.82 m/s^2.
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