Jess wants to make her house more energy efficient. Insulating her loft, which will cost £460 and save £25 per year, is better long-term option. Therefore, option B is correct.
What is energy ?In order to accomplish work and to produce heat and light, energy must be transferred to a body or to a physical system. Energy is the quantitative attribute that does this. Energy is a preserved resource; according to the rule of conservation of energy, energy can only be transformed from one form to another and cannot be created or destroyed.
Computers, vehicles, communications, state-of-the-art medical technology, and many other things are all powered by energy. The demand for dependable and economical energy is especially pressing for emerging countries. It may enhance things or perhaps save lives.
A turbine generator set transforms mechanical energy into electrical energy to produce electricity. Natural gas, coal, nuclear fission, biomass, petroleum, geothermal, and solar thermal are examples of energy sources where the heat generated is used to produce steam.
Thus, option B is correct.
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A 2 kg billiard green ball is moving toward the 2 kg white billiard ball on a pool table. The green ball is moving with an initial speed of 4 m/s and the white ball is at rest. The two balls collide and move apart. The white ball moves away from the green ball with a speed of -6 m/s. With what speed does the green ball move away?
Answer:
10m/s
Explanation:
collisions results in objects sticking together or not sticking together after collision and so they do move with a common velocity or uncommon velocity respectively.
Parameters from the question:
Mass of green billiard balls, m1=2kg
Mass of white billiard balls, m2=2kg
Initial velocity for green billiard balls ,u1=4m/s
Initial velocity for white billiard balls ,u2 = 0m/s( since the body is at rest meaning it wasn't moving)
Final velocity of green billiard ball after collision is,v1= unknown
Final velocity of white green billiard ball after collision is, V2 = -6m/s.
Now from Newton's third law of motion that action and reaction must be equal and opposite;hence change in momentum before collision would be the same after collision since energy is conserved.
Hence,
m1U1 + m2U2 = m1V1 +m2V2
2×4 + 2×0 = 2×V1 + 2× (-6)
8 = 2V1 -12
8+12=2V1
20=2V1
10=V1
V1=10m/s
What is the magnitude of impulse of a 2.7 gram ping pong ball initially moving at 15 m/s, if hit by a ping pong paddle and then moves the opposite direction at 14/ms
Answer:
impulse = 0.0783 kg.m/s
Explanation:
The impulse is the product of the force and an interval of time. This can be represented in terms of the mass of the body and the change in the velocity of the body in such a time:
[tex]F\Delta t=m\Delta v[/tex] [tex]=|m(v_f-v_i)|[/tex]
m: mass of the body = 2.7gm = 0.0027 kg
vf: final velocity = -14m/s
vi: initial velocity = 15m/s
vf is negative because the direction of the ball is opposite to the initial direction:
[tex]|m(v_f-v_i)|=|(0.0027kg)(-14m/s-15m/s)|=0.0783\frac{kg.m}{s}[/tex]
hence, the impulse of the ping pong ball is 0.0783 kg.m/s
A horse runs for 15 seconds to the south at a speed of 12 m/s. What is the
displacement of the horse in this time?
A. 180 m south
B. 150 m south
C. 150 m
D. 180 m
Answer: 180 m south
Explanation:
The displacement of the horse in this time is 180 m south. The correct option is A.
What is displacement?The displacement is the shortest distance travelled by the particle. It is the vector quantity which re[presents both the magnitude and direction.
Velocity is the time rate of change of displacement with time.
Given is a horse runs for 15 seconds to the south at a speed of 12 m/s. So, the displacement is
Displacement = Speed x Time
Put the values, we get
Displacement = 12 m/s x 15s
= 180 m
Thus, the displacement of the horse in this time is 180 m south.
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calculate the pressure exerted by a man having mass 50 kg standing on one feet having area 500cm2
Answer:
9800 Pa
Explanation:
Data: pressure-?
Force- mass ×acceleration
= 50× 9.8m/s^2
=490N
Area= 500cm^2=0.05m^2
pressure= force/ area
p=F/A
P= (490N)/( 0.05m^2)
=9800 Pa
When the kinetic energy of particles in a substance decreases, what also decreases?
93
The size of the particles in the substance.
The number of particles in the substance.
The substance's specific heat.
The substance's temperature.
Answer: D
The substance's temperature
Explanation:
According to kinetic theory, increase in temperature causes increase in kinetic energy of particles in a system.
When the kinetic energy of particles in a substance decreases, it has nothing to do with the size of the particles and the specific heat capacity of the particles or substance. But it a clear indication that the substance temperature has also decreased.
Answer:
D
Explanation:
A car accelerates from 10m/s to 20m/s over a distance of 80m. What is its acceleration?
Answer:
0.125m/s^2
Explanation:
20-10=10
10 divided by 80=0.125m/s^2
The average velocity of the car is 15 m/s. The time taken to travel over the distance with this velocity is 5.3 seconds. Then the acceleration of the car is 1.8 m/s².
Wat is acceleration ?Acceleration is a physical quantity measuring the rate of change in velocity of a moving object. Like velocity, acceleration is a vector quantity having magnitude and direction.
Acceleration is the ratio of change in velocity to the change in time.
a = Δv/Δt
Given, the car is accelerating from 10 to 20 m/s. Hence, it travelled with average velocity of 15 m/s over the distance of 80 m.
Then , time taken = distance/velocity
t = 80 m/15 m/s = 5.3 s
Acceleration = Δv/t = (20 -10 m/s) /5.3 s = 1.8 m/s².
Therefore, the acceleration of the car is about 1.8 m/s².
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why is no one helping?
Answer:
First one is hyperopia, second is myopia
Explanation:
Hyperopia is when the image is formed behind the retina.
Myopia is when images are formed infront of the retina.
If the potential difference across the bulb in a camping lantern is 9.0 V, what is the
potential difference across the cells used to power it?
Answer:
9.0 V.
Explanation:
battery gives the voltage of 9.0 V to the lantern to use it.
The voltage across the bulb in camping lanterns is equal to the potential difference across the cells that are used to power it. So, 9 V.
What is meant by potential difference ?Potential difference between two points is defined as the amount of work required to move a unit positive charge along any path between two places in the electric field without accelerating the charge.
Here,
While the one point has a lower potential, the other one has a higher potential. The term voltage or potential difference refers to the charge difference between higher and lower potentials.
The force needed for the electrons to move through a circuit is provided by the voltage or potential difference.
In a series circuit, the voltage across a bulb is equal to the voltage across the battery only if the bulb and the battery are the only components in the circuit.
Hence,
The voltage across the bulb in camping lanterns is equal to the potential difference across the cells that are used to power it. So, 9 V.
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Is a 5kg ball is rolling to the right and has a velocity of 4 m/s what is the momentum of the ball
Answer:
∆p = 20 kg * m/s
Explanation:
The change in momentum is the mass of the body multiplied by the change in its velocity.
In formula form ∆p = m * ( ∆v ).
with m = 5 kg and ∆v = 4 m/s
∆p = 5 kg * 4 m/s
∆p = 20 kg * m/s
What is the acceleration if velocity increases from 10 m/s to 15m/s after travelling a distance of 5 metre
Answer:
a=1.25m/s²
Explanation:
GIVEN DATA
vi=10m/s
vf=15m/s
S=5m
TO FIND
a=?
SOLUTION
by using third equation of motion
2as=(vf)²-(vi)²
2a(5m)=(15m/s)²-(10m/s)²
10m×a=225m²/s²-100m²/s²
10m×a=125m²/s²
a=[tex]\frac{125}{10}[/tex]
a=12.5m/s²
3.
If you are part of a center or network, you can use program-level data to
A. change the way you record and maintain information.
B. identify professional development needs.
C. improve the management systems to support child learning.
D. change the way you speak with families
Answer:
A
Explanation:
Answer: A
Explanation:
A student with a mass of 66.0 kg climbs a staircase in 44.0 s. If the distance between the base and the top of the staircase is 14.0 m, how much power will the student deliver by climbing the stairs
[tex]power = 205.8 \: watt \\ solution \\ mass = 66 \: kg \\ time = 44 \: sec \\ distance = 14 \\ now \\ power = \frac{w}{t} \\ \: \: \: \: \: \: \: \: = \frac{f \times d}{t} \\ \: \: \: \: \: = \frac{m \times g \times d}{t} \\ \: \: \: \: \: \: = \frac{66 \times 9.8 \times 14}{44} \\ \: \: \: \: = \frac{9055.2}{44} \\ \: \: \: \: \: = 205.8 \: watt \\ hope \: it \: helps[/tex]
a 50.0kg bicyclist on a 10.0kg bicycle speeds up from a 5.00m/s to 10.0m/s
Answer:
The total kinetic energy before accelerating = 750 JThe total kinetic energy after accelerating = 3,000 JTotal work done = 2,250 JExplanation:
Given:
Mass of bicyclist = 50 kg
Mass of bicycle = 10 kg
Initial velocity (u) = 5 m/s
Final velocity (v) = 10 m/s
Find:
(a) What was the total kinetic energy before accelerating = ?
(b) What was the total kinetic energy after accelerating = ?
(c) How much work was done to increase the kinetic energy of the bicyclist = ?
Computation:
Total mass (M) = 50 kg + 10 kg = 60 kg
1. The total kinetic energy before accelerating = 1/2[Mu²]
The total kinetic energy before accelerating = 0.5[(60)(5)²]
The total kinetic energy before accelerating = 750 J
2. The total kinetic energy after accelerating = 1/2[Mv²]
The total kinetic energy after accelerating = 0.5[(60)(10)²]
The total kinetic energy after accelerating = 3,000 J
3. Total work done = Δ K.E
Total work done = 3,000 J - 750 J
Total work done = 2,250 J
What is the centripetal force of an object undergoing uniform circular motion when its radius is doubled and its speed remains constant?
A.
the same as before
B.
twice as great as before
C.
half as great as before
D.
four times as great as before
Answer:
C
Explanation:
Now the centripetal force is that force that keeps the object on course along the circle;
This is expressed mathematically as ;
F = mv^2/ r
Where F - centripetal force
m- mass of the object
v- velocity of the object
r- raduis
Note from the expression as r increases F decreases so if v and the mass is constant if r doubles F will reduce by half.
Answer:
C. half as great as before
Explanation:
can someone help what are the common branches of physics
Answer: Dear Buddy ,the common brnches os physics are given below:
Explanation:
Mechanics
Classical physics
Modern physics
Thermodynamics
Electricity
Magnetism
Geo physics
Plasma physics
Optics
Sound and oscillation
Electronics
Chemical physics
Engineering physics
Solid state physics
Quantum physics
Nuclear physics
Particle physics
Bio physics
Astrophysics
Condensed matter physics
hope it helps
Answer:
Engineering is one of branches that uses physics mainly the most
Explanation:
as for engineering requires mathematics and physics principles in their everyday routine to calculate and measure accordingly to manufactur a product.
A sheet of paper 3.0 cm by 4.0 cm is lying on the desk. If the atmospheric pressure is 1.013105 Pa, what is the total force exerted on the top side of the paper by the atmosphere?
Answer:
132.56N
Explanation:
Pressure is defined as force per unit area.
Expressed mathematically as;
P = F/A
Where P-pressure
F-force
A-area
From the above formula,
F= P×A
= 1.1013 × 10^5 × (3×4/10000)
= 11.013×12 =132.56N
Note: the unit of measure in cm is converted to m and since 100cm makes 1m for each sides 3cm and 4cm we convert to 'm' by dividing by 100 twice giving division by 10000)
The unit of measure Pa means Pascal and is the same as N/m2
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As light shines from air to water, the index of refraction is 1.02 and the angle of
incidence is 38.0 °. What is the light's angle of refraction?
29.8°
32.5°
37.1°
39.8°
Answer:
37.1°
Explanation:
Chemical potential energy can be released into
energy
OA) heat
OB) elastic
OC) potential
Answer:
C Potential
Explanation:
Chemical potential energy is a form of potential energy related to the structural arrangement of atoms or molecules. This arrangement may be the result of chemical bonds within a molecule or otherwise. Chemical energy of a chemical substance can be transformed to other forms of energy by a chemical reaction.
Salt is dissolved in a flask of tap water . Distilling the mixture causes the salt to separate from the water. Which type of energy is required to begin the distilling process
What is the name of the change in state by which some more energetic molecules in a liquid leave the surface, leaving the rest of the liquid slightly cooler.
Answer:
evaporation
Explanation:
vapor is having higher temperature (also energy) that the liquid it left behind.
that's why the water vapor leave the surface of water which can only have a maximum temperature as 100°C
What is the most likely reason why these early flowers gradually changed to many different types of flowers over time?
Answer:
The flowers adapted to environmental conditions.
Explanation:
what is brightness. help asap
Answer:
The subjective visual sensation related to the intensity of light emanating from a surface or from a point source.
Investigator Robbins is called to the scene of a robbery. The officer on the scene thinks that the suspect entered the home from the garage. As Investigator Robbins checks over the house, he does not find any evidence of forced entry. He cannot find any physical evidence near the garage door at all. There is a window open above the kitchen sink and footprints in the mud under the window outside. Based on his examination, what conclusion might Investigator Robbins make?
1. The officer was correct; the garage was the point of entry.
2. There is no evidence to indicate that anyone entered the home.
3. The officer's conclusion was mistaken, and a suspect may have entered through the window.
4. The garage was the point of entry, but the window was the escape route.
Answer:
3
Explanation:
Since the evidence found points to the window on investigation remember there was a foot print below the window as well as the window been opened.
A wire having resistance 20 ohm is bent to make a closed square.What is the resistance across the diagonal of square?
Answer:
5 Ω
Explanation:
When it is bent into a square, each side of the square will get 5 Ω resistance. As considered diagonally ,path of the wire between to diagonal points is the two sides of the square (that is half the length of the wire connected in parallel position). Which gives 10 ohm parallel to 10 ohm wire. So it finally read as 5 Ω wire
A train is moving west with an initial velocity of 20m/s accelerates at 4m/s for 10 seconds during this time the train moves a distance
Answer:
400m
Explanation:
From Newton's law of motion;
S = ut + 1/2 at2
Where U is initial velocity
a is acceleration
t is velocity hence;
S is distance covered
S = 20×10 + 1/2 × 4×(10)^2
= 200 + 200 = 400m
A 2kg object is dropped from a height 10m.Calculate the speed of the object after it has fallen 5m, assuming there is no resistance. g= 10 N/kg
Answer:
10m/s
Explanation:
[tex]d=v_ot+\dfrac{1}{2}at^2[/tex]
Since there is no initial velocity as the object is dropped, you can write the following equation:
[tex]5=\dfrac{1}{2}(10)t^2 \\\\1=t^2 \\\\t=1[/tex]
Now that you know how long the fall took, you can use another physics equation to find the velocity at that point.
[tex]v_f=v_o+at[/tex]
Since there once again is no initial velocity, you can rewrite this as:
[tex]v_f=at=(10)(1)=10m/s[/tex]
Hope this helps!
The kinetic energy the object has at any point during the fall is exactly the potential energy it lost by falling to that height.
Potential energy = (mass) · (gravity) · (height)
Change of potential energy = (mass) · (gravity) · (change of height)
Change of potential energy = (2 kg) · (10 m/s ) · (-5 m)
Change of potential energy = 100 Joules
Kinetic energy = (1/2) · (mass) · (speed²)
Kinetic energy = (1 kg) · (speed² )
100 J = (1 kg) · (speed²)
Speed² = (100 J) / (1 kg)
Speed² = (100 kg-m²/s²) / (1 kg)
Speed² = (100 m²/s²)
Speed = 10 m/s
The power of a machine is 6000 W. This machine is scheduled for design improvements. Engineers have reduced the
time for the output by one half from 15 s to 7.5 s. What work would be required to cut the time in half.
Step #1
Step #2
Step #3
Explanation:
Work = power × time
W = (6000 W) (7.5 s)
W = 45,000 J
a motorcar is moving with a velocity of 108 km / h and it takes 4s to stop after the brakes are applied calculate the force exerted by the brakes on the motorcar if it's mass along with the passengers is 1000 kg
Answer: - 7500N
Explanation:
Given the following :
Initial Velocity of car = 108km/hr
Time taken to stop after applying brakes = 4s
Mass of passengers in car = 1000kg
Force exerted by the brakes on the car =?
After 4s, then final Velocity (V) = 0
Initial Velocity (u) of the car = 108km/hr
108km/hr = (108 × 1000)m ÷ (3600)s = 30m/s
Force exerted = mass(m) × acceleration(a)
Acceleration of car = Change in Velocity with time
a = (v - u) / t
a = (0 - 30) / 4
a = - 30/ 4
a = - 7.5m/s^2
Therefore,
Force exerted = mass(m) × acceleration(a)
Force exerted = 1000kg × (-7.5)m/s^2
Force exerted = - 7500N
Answer:
The force exerted by the brakes on the motor car is -7500 N.
Explanation:
Given :-
Mass of the motor car along with passengers (m)= 1000 kgInitial velocity (u) = 108 km/hTime taken (t) = 4 sTo find :-
The force exerted by the brakes on the motor car.Solution :-
Since the car stops, the final velocity (v) will be 0 m/s.
• Initial velocity (u) = 108 km/h.
Converting initial velocity into m/s.
We know that,[tex] \sf{1\:km/h=\dfrac{5}{18}\:m/s}[/tex]
Then initial velocity,
= [108 × 5/18 ] m/s
= 30 m/s
Now find the force exerted by the brakes.
★ Formula used :
[tex]{\boxed{\sf{F=\dfrac{m(v-u)}{t}}}}[/tex]
[put values][tex]:\implies \sf \: F= \dfrac{1000(0 - 30)}{ 4} \\ \\ : \implies \sf \: F \: = \dfrac{ - 30000}{4} \\ \\ : \implies \sf \: F \: = - 7500[/tex]
The force exerted by the brakes on the motor car = -7500 N.
•The negative sign of force(F) means that the force was applied in opposite direction of motion.
__________________how can I get good grades in physics?
Answer:
work idk
Explanation:
if you pay attention and make notes of important things in your unit then it'll help get good grade
ask your teacher for extra credit or if there's anything you can do to raise your grade
Write down any four points that should be considered during household wiring
Answer:
USE RUBBER CLOVES
USE A PLIER
USE CONDUCTIVE WIRES
SWITHC OFF THE MAIN SWITCH WHILE WIRRING
Explanation:
