7. It takes 1 second to hear the reflection of a loud noise made in front of a large barrier. If
the speed of sound in air is 340 m/s, how far away is the barrier?
A. 85 m
B. 170 m
C. 340 m
D. 680 m
Answer:
C 340 m
Explanation:
may i be marked brainliest?
A 700 kg car going 12 m/s speeds up to 30.6 m/s in 7 seconds. How much work was done to increase its speed?
Answer:
Approximately [tex]2.8 \times 10^{5} \; \rm J[/tex] (assuming that the car is moving on level ground, and that there is no friction to hinder the motion of the car.)
Explanation:
Formula for the kinetic energy, [tex]\rm KE[/tex], of an object of [tex]m[/tex] travelling at velocity [tex]v[/tex]:
[tex]\displaystyle \text{KE} = \frac{1}{2}\, m \cdot v^{2}[/tex].
Let [tex]v_1[/tex] and [tex]v_2[/tex] denote the velocity of this car before and after the acceleration.
Kinetic energy of this car before the acceleration:
[tex]\begin{aligned}\text{KE}_1 &= \frac{1}{2}\, m \cdot {v_1}^{2} \\ &= \frac{1}{2} \times 700\; \rm kg \times (12\; \rm m \cdot s^{-1})^{2} \\ &\approx 5.0 \times 10^{4}\; \rm J\end{aligned}[/tex].
Kinetic energy of this car after the acceleration:
[tex]\begin{aligned}\text{KE}_2 &= \frac{1}{2}\, m \cdot {v_2}^{2} \\ &= \frac{1}{2} \times 700\; \rm kg \times (30.6\; \rm m \cdot s^{-1})^{2} \\ &\approx 3.3\times 10^{6}\; \rm J\end{aligned}[/tex].
Assume that this car was travelling on level ground. Also assume that there is no friction to hinder the motion of this car. The work of the engine of this car would be equal to the amount of [tex]\rm KE[/tex] that the car has gained:
[tex]\rm KE_2 - KE_1 \approx 2.8\times 10^{5}\; \rm J[/tex].
How much kinetic energy does a 2 kg ball have if it is going 5 m/s ?
Explanation:
mass(m)=2 kg
velocity(v)=5m/s
Now,
Kinetic energy(K.E.)=1/2mvsq
=1/2×2×5sq
=25
where,sq=square(2)
How does this relate to Newton's second law?
Two balls with different weights (tennis ball and basket ball) are dropped from the same height to see which one will land first
Answer:
In ideal case, when no resistive forces are present then both the balls will reach the ground simultaneously. This is because acceleration due to gravity is independent of mass of the falling object. i.e. g = GM/R² where G = 6.67×10²³ Nm²/kg², M = mass of earth and R is radius of earth.
Let us assume that both are metallic balls. In such case, we have to take into account the magnetic field of earth (which will give rise to eddy currents, and these eddy currents will be more, if surface area will be more) and viscous drag of air ( viscous drag is proportional to radius of falling ball), then bigger ball will take slightly more time than the smaller ball.
Explanation:
In ideal case, when no resistive forces are present then both the balls will reach the ground simultaneously. This is because acceleration due to gravity is independent of mass of the falling object. i.e. g = GM/R² where G = 6.67×10²³ Nm²/kg², M = mass of earth and R is radius of earth.
Let us assume that both are metallic balls. In such case, we have to take into account the magnetic field of earth (which will give rise to eddy currents, and these eddy currents will be more, if surface area will be more) and viscous drag of air ( viscous drag is proportional to radius of falling ball), then bigger ball will take slightly more time than the smaller ball.
Which example is NOT a part of the electromagnetic spectrum?
Group of answer choices
electricity
microwaves
violet light
radio waves
Which statements did both Aristotle and Ptolemy assume? Select two options.
The Sun was the center of the solar system.
Bodies in space traveled in circles.
Epicycles explained the “looping” movement of the planets.
The planets revolved around the Earth.
The stars in the sky are other suns.
Answer:
Bodies in space traveled in circles.
The planets revolved around the Earth.
Explanation:
Answer: b and d
Explanation:
got it right
Which can cause physical weathering of rock?
A acid
B oxygen
C sun
D wind
Answer:
D wind
Explanation:
Heavy winds may cause much damage to the Earth along with rain and extreme temperature changes.
A car traveling towards east at 40 m/s and turns towards left and travels at same speed. The change in velocity is
Answer:
Explanation:
In physics the term velocity is always a vector. All that means is that it's got a direction with it. which also means this vehicle that was traveling in the east direction and then turned left is and is now , maybe traveling in a north direction. Making the guesses that the car was traveling due East and is now traveling due North, then the car has changed it's velocity by 40 m/s. By The Way do you happen to know how fast 40 m/s is? it's about 144 Kph :0 or about 90 MPH so this guy is also speeding :D, write him a ticket ... :P
A ray of light strikes a plane mirror at an angle of incidence equal to 35°. The angle between
the incident ray and the reflected ray is
A)
70°
B)
0°
C)
55°
D)
35°
Answer:
55 degrees
Explanation:
A ray of light strikes a plane mirror at an angle of incidence. The angle between the incident ray and the reflected ray is 70°. The correct option is A.
What is law of reflection?The law states that angle of incidence of the incident ray is equal to the angle of reflection through a plane surface.
Here, angle of incidence of light on a plane mirror is 35°, then the angle of reflection will also be 35°.
i = r = 35°
Then the angle between the incident ray and the reflected ray will be
i +r = 35 + 35 =70°
Thus, the correct option is A.
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The properties of metals depend mainly on the number and arrangement of neutrons
True
False
Answer:
False
Explanation:
Electrons
GIVING BRAINLIEST PLEASE HELP!!
-if you answer correctly ill give you brainliest which will give you 20pts-
Answer:
b,c and d
Explanation:
What is a Satellite in your own words??
(Science)
Answer:
What I think a Satellite is...
Explanation:
A satellite may be a moon, planet or machine that circles a planet or star. For example, Earth could be a satellite since it circles the sun. Moreover, the moon may be a obsequious since it circles Soil. As a rule, the word "satellite" refers to a machine that's propelled into space and moves around Earth or another planet in space.
Please.rate.me.a.five:)
Two charges are separated by a distance r. The distance between the charges is tripled to 3r. If the original force between the charges was 45N what is the new force between the charges A.5N B.15N C.75N D.135N
Answer:
5N
Explanation:
The formula formula for calculating the force between charges is expressed as;
F = kq1q2/r²
If two charges are separated by a distance r and a force between them is 45N, then;
45 = kq1q2/r² ....1
If the distance between the charges is tripled to 3r, then;
F = kq1q2/(3r)²
F = kq1q2/9r² ... 2
Divide both expressions
45/F = (kq1q2/r²)/(kq1q2/9r²)
45/F = kq1q2/r² * 9r²/kq1q2
45/F = 9
9F = 45
F = 45/9
F = 5N
Hence the new force between them will be 5N
2. Using the solar system data in the
reference table, rank the following
pairs of planets according to the
gravitational force they exert on
each other, from least to greatest.
Specifically indicate any ties.
Mass. Average radius
(kgÅ~1024). (mÅ~106)
Mercury. 0.330. 2.44
Venus 4.87 6.05
Earth 5.97 6.38
Jupiter 1899 71.5
Saturn 569 60.3
A. Mercury and Venus, when
5.0Å~107 km apart
B. Jupiter and Saturn, when
6.6Å~108 km apart
C. Jupiter and Earth, when
6.3Å~108 km apart
D. Mercury and Earth, when
9.2Å~107 km apart
E. Jupiter and Mercury, when
7.2Å~108 km apart
Answer:
I'm pretty sure the answer would be C.
find ways you can change the total energy
Answer:
The ways to change the total energy are to either make the hill taller to increase it or make the hill lower to decrease the total energy.
Explanation:
The total mechanical energy of a system is the sum of the total kinetic energy and total potential energy.
john and kate live in the regions marked on the map. john experiences severe winters, with snowstorms and blizzards. in contrast, kate hardly ever experiences temperatures near or below freezing. which of the following statements explain the climate differences in these locations??
Answer:
A. Kate’s location is at a lower latitude.
C. Kate’s location absorbs sunlight that travels a shorter distance through the atmosphere.
Explanation:
^
Answer:
edmentum :-))
Explanation:
NHT0015
16. A metal rod is heated increasing its temperature
by 10°C. The fractional change in its length is
1 *10-4. If a plate of same metal is heated raising
its temperature by 5°C, the fractional change in
its area will be .-
(1) 1 x 10-4
(2) 0.5 x 10-4
(3) 2 x 10-4
(4) 3 x 10-4
Answer:
(1) 1×10⁻⁴
Explanation:
From the question,
α = (ΔL/L)/(ΔT)............. Equation 1
Where α = linear expansivity of the metal plate, ΔL/L = Fractional change in Length, ΔT = Rise in temperature.
Given: ΔL/L = 1×10⁻⁴, ΔT = 10°C
Substitute these values into equation 1
α = 1×10⁻⁴/10
α = 1×10⁻⁵ °C⁻¹ .
β = (ΔA/A)/ΔT................... Equation 2
Where β = Coefficient of Area expansivity, ΔA/A = Fractional change in area.
make ΔA/A the subject of the equation
ΔA/A = β×ΔT.......................... Equation 3
But,
β = 2α.......................... Equation 4
Substitute equation 4 into equation 3
ΔA/A = 2α×ΔT................ Equation 5
Given: ΔT = 5°C, α = 1×10⁻⁵ °C⁻¹
Substitute into equation 5
ΔA/A = ( 2)×(1×10⁻⁵)×(5)
ΔA/A = 10×10⁻⁵
ΔA/A = 1×10⁻⁴
Hence the right option is (1) 1×10⁻⁴
Clay bricks are used as building materials in construction. Do some research on specific heat capacities of brick, concrete, stone etc. and advise on what this means for society.
Answer:
It means it is the main building block material for society.
Specific heat is the amount of heat energy that causes a unit increase in temperature by required to be added to the unit mass of the substance. It can be measured by the heat capacity of a particular substance. The unit of specific heat is joule/kg/kelvin.
Material Specific heat capacity Thermal conductivity
Clay 1000 0.60
stone 1000 1.8
brick 800 0.73
concrete 1000 1.13
Advice on what this means for society:
Thermal interaction in between indoor and outdoor environments regulated by wall components.The structural and thermal properties influence the behavior of building and fabricating the bricks, stone and others. Clay Bricks are durable, and natural of stable value. A modern building must comply with numerous ecological and economic demands.Learn more about specific heats:
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Chemical reactions and nuclear reactions cause matter to change in different ways. Which two statements describe how matter changes only in a nuclear reaction? PLZZZ HELP ME ASAP!!
A.) Each atomic nucleus changes
B.) The electrons of atoms are rearranged
C.) No new elements are formed
D.) Atoms of new elements are formed
Answer:
Explanation:
A and D was the right answer for me.
The two statements describe how matter changes only in a nuclear reaction are each atomic nucleus changes and atoms of new elements are formed.
What is nuclear reaction?Nuclear reactions is the nuclei transformation process in which one or more nuclides are produced from the collisions between an atomic nucleus and a subatomic particle (neutrons or protons)
In this reaction, the nucleus changes because, the number of protons or neutron decreases. New element with new atomic number and nucleus is formed.
Thus, the correct option is A and D.
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The time lag between education of a muscle cell and the beginning of contraction is known as the ______
A periodic wave with wavelength
- 2 m has frequency f = 4 Hz.
What is the wave's speed?
Answer:
-8m/s
Explanation:
v=wavelength*f=-2*4=-8m/s
6. Fig. 3.1 shows a pond that is kept at a conslant depth by a pressure-operated valve in the
base.
water
pressure oporated
va
outlet
spring
Fig. 3.1
(a) The pond is kept at a depth of 2.0m. The density of water is 1000 kam
Calculate the water pressure on the valve.
A. 20 Pa
B.
20000 Pa
o 10000 Pa
D. 100 Pa
Answer: I didnt understand it sorrryryyyyyyy
Explanation:
Which is an example of the cycling of matter from one sphere to another?
A a puddle of water evaporating and rising into the atmosphere
B animals obtaining energy from plants
C heat energy from the sun warming the land
D heat energy from the sun warming the oceans
In the example of a hammer hitting a nail, which is hit harder? the nail, the hammer, or they both hit equally?
Answer:
both hit qaulity
Explanation:
Newton's Third Law says that every interaction involves two forces - in this case (1) hammer pushes nail, and (2) nail pushes hammer. When a hammer hits a nail, Newton's Third Law says that the force that the hammer exerts on the nail is exactly the same size as the force the nail exerts on the hammer.
WILL GIVE BRANLIEST
can you find a magnet with only a north pole? why or why not?
A factory has 1200 workers of which 720 are male and the rast are female what percent of workers are female
Answer:
Percent of Female Workers = 40%
Explanation:
The percentage of the female workers in the given group of workers can be easily found by the following formula:
[tex]Percent\ of\ Female\ Workers = \frac{No.\ of\ Female\ Workers}{Total\ No.\ of\ Workers}\ x\ 100\%[/tex]
where,
Total No. of Workers = 1200
No. of Female Workers = Total Workers - No. of Male Workers
No. of Female Workers = 1200 - 720 = 480
Therefore,
[tex]Percent\ of\ Female\ Workers = \frac{480}{1200}\ x\ 100\%[/tex]
Percent of Female Workers = 40%
I really really really need help with this one question, if answered correctly or attempted will get brainliest :)
For the circuit shown with a 12.0 V battery, what are the currents through each resistor and the voltage drops across each resistor?
Answer:
i belive it is R 24
Explanation:
may i be marked brainliest?
Does anyone know 19 and 20 ??
When the car engine is working normally, 2 kg of coolant passes through the radiator each second. The temperature of the coolant falls from 112 °C to 97 °C. Calculate the energy transferred each second from the coolant. Specific heat capacity of the coolant = 3800 J/kg °C
Answer: 114 kJ/s
Explanation: Q = mcΔT = 2 kg · 3800 J/(kg C) ·15 C
Which of the following effects results from the interference of two sound
waves that have slightly different frequencies?
A. Beats
B. Intensity
C. Loudness
D. Echoes
SUBMI
Answer:beats
Explanation:l got it right gang
Beats effects results from the interference of two sound waves that have slightly different frequencies.
What is beats?
Beats are produced by the superposition of two waves of slightly different frequencies but identical amplitudes. The waves alternate in time between constructive interference and destructive interference, giving the resulting wave a time-varying amplitude.
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