Answer:
Its Generation of Heat. or "D"Explanation:
Friction causes generation of heat and causes increased wear and tear.
The friction is a resistive force and is related to heat energy, so an increase in friction results in the generation of heat, so option D is correct.
What is friction?Two solid objects cannot roll or slide over one another due to the force of friction. Although frictional forces can be useful, such as the traction needed to walk without slipping, they can also present a large degree of resistance to motion. Automobile engines need about 20% of their power to overcome frictional forces in moving parts.
The fundamental source of friction between metals appears to be the adhesion forces between the contact zones of the surfaces, which are always microscopically uneven. Friction is produced by shearing, these "welded" seams, and the rubbing action of the rougher, tougher surface against the softer, smoother surface.
The friction is a resistive force trying to oppose the force applied As friction is related to heat when we increase the heat, the friction increases, and vice versa.
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Proved that
V = u+at
Answer:
[tex]\sf Proof \ below[/tex]
Explanation:
We know that acceleration is change in velocity over time.
[tex]\sf a=\frac{\triangle v}{t}[/tex]
[tex]\sf a=\frac{v-u}{t}[/tex]
v is the final velocity and u is the initial velocity.
Solve for v.
Multiply both sides by t.
[tex]\sf at=v-u[/tex]
Add u to both sides.
[tex]\sf at + u=v[/tex]
Answer:
Acceleration = v-u/t when we flip -u and t to right hand side
then -u changes to plus and denominator t changes to numerator
then then this equations becomes v=u+at
Explanation:
A mobile starts and travels 225 m with an acceleration of (- 3.5i + 4.5j) 2 along a rectilinear path. Determine:
a) The time spent
b) The final speed
c) The average speed I hope you can help me.
Answer:
a) 8.89 s
b) 50.6 m/s
c) 25.3 m/s
Explanation:
d = 225 m
v₀ = 0 m/s
a = (-3.5i + 4.5j) m/s²
First, find the magnitude of the acceleration.
a = √((-3.5)² + (4.5)²) m/s²
a = 5.7 m/s²
a) Find t
Δx = v₀ t + ½ at²
225 m = (0 m/s) t + ½ (5.7 m/s²) t²
t = 8.89 s
b) Find v
v² = v₀² + 2aΔx
v² = (0 m/s)² + 2 (5.7 m/s²) (225 m)
v = 50.6 m/s
c) Find v_avg
v_avg = Δx / t
v_avg = 225 m / 8.89 s
v_avg = 25.3 m/s
Or, for constant acceleration:
v_avg = (v₀ + v) / 2
v_avg = (0 m/s + 50.6 m/s) / 2
v_avg = 25.3 m/s
Which of the following scientists proposed the theories of relativity?
A. Galileo Galilei
B. Johannes Kepler
C. Albert Einstein
D. Sir Isaac Newton
Answer:
c) Albert Einstein,
Explanation:
in his theory of special relativity, determined that the laws of physics are the same for all non-accelerating observers, and he showed that the speed of light within a vacuum is the same no matter the speed at which an observer travels.
hope this helped
-lvr
A firework is initially at rest explodes into 2 pieces one of which weighing 2.0 kg flies to the right at15 m/s the other piece flies to tje left at 20m/s wjat is tge mass of firework before explosion??
Answer:
3.5 kg
Explanation:
use the equation; (m1v1i) + (m2v2i) = (m1v1f) + (m2v2f)
= m1(0) - m1v1f = m2v2f - m2(0)
= (-2.0)(15)/-20
= 1.5 kg
then add the other piece (2.0kg)
1.5 + 2.0 = 3.5 kg
The mass of firework before explosion is 3.50kg.
mass flying to right m1 = 2kg
v1 = 15 m/s
mass flying to left m2 = ?
v2 = - 20m/s
initial velocity u = 0
by conservation of linear momentum
m1v1+ m2v2 = (m1+m2 ) u
2x 15- m2x 20 = 0
m2 = 1.50kg
therefore mass of firework before explosion
m1+m2
2+ 1.50
= 3.50kg
What is mass?Mass is the amount of matter in a physical body. It also measures the body's inertia, the resistance to acceleration when a net force is applied. The mass of an object also determines its gravitational force on other objects. The basic SI unit of mass is the kilogram.
Body mass is always constant. One way to calculate mass:
mass = volume × density. Weight is a measure of the gravitational force acting on a mass. The SI unit of mass is the "kilogram".
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Which reverses the flow of current through
an electric motor?
Answer:
a commutator
Explanation:
Salt compounds are commonly used to melt ice that forms on sidewalks in the winter. A common chemical that is used to melt sidewalk ice is calcium chloride, CaCl2(s). When calcium chloride dissolves into solution is releases thermal energy which aides in melting
the ice.
The molar mass of water is 18.02 g/mol
The thermal energy, in kilojoules (kJ) that must be released from the calcium chloride,
CaCl2(s), to melt 10.0 kg of ice, expressed in scientific notation is a.bc x 104 k).
46
55
The values of a, b, c, and d.
Answer:
The values of a, b, c and d are
a = 3, b = 3, c = 4 and d = 3
Explanation:
The quantity of heat needed to melt the ice is given by Q = mL where m = mass of ice and L = latent heat of fusion of ice = 334 kJ/kg. This quanity of heat is also the thermal energy needed to be released by the calcium chloride, CaCl₂
Now, the mass of ice = 10 kg. So,
Q = mL
Q = 10 kg × 334 kJ/kg
Q = 3340 kJ
In scientific notation,
Q = 3.34 × 10³ kJ
So the thermal energy needed to be released by the calcium chloride is 3.34 × 10³ kJ
Comparing Q = 3.34 × 10³ kJ with a.bc × [tex]10^{d}[/tex] kJ
So, a = 3, b = 3, c = 4 and d = 3
The values of a, b, c and d are
a = 3, b = 3, c = 4 and d = 3
PLEASE HELP ME ASAP. IT'S VERY IMPORTANT
Answer:
1) a. 52.41 m/s
b. The skier will be going 15.35 m/s slower
2) 103.68 m
3) 35,127 J
4) a. 88.825 kJ
(b) 16.36 %
5) 3,071.12 J
Explanation:
1) a. The given height of the hill, h = 140.0 m
The mass of the skier at the top of the hill, m = 85.0 kg
The acceleration due to gravity, g = 9.81 m/s²
The initial potential energy, P.E of the skier = m×g×h = 85.0×140.0×9.81 = 116739 J
From the principle of conservation of energy, we have;
The potential energy, P.E. lost = The gain in kinetic energy, K.E.
m×g×h = 1/2×m×v²
116739 J = 1/2×85.0×v²
v² = 116739/(1/2*85.0)= 2746.8 m²/s²
v = √(2746.8 m²/s²) = 52.41 m/s
b. From 70 m up, we have;
The initial potential energy, P.E., of the skier is now = 85.0×70×9.81 = 58,369.5 J
The potential energy, P.E. lost = The gain in kinetic energy, K.E.
58,369.5 J = 1/2×85.0×v²
v² = 58,369.5/(1/2*85.0) = 1373.4 m²/s²
v = 37.06 m/s
The skier will be going 52.41 - 37.06 = 15.35 m/s slower
The skier will be going 15.35 m/s slower
2) From the principle of conservation of energy, the amount of work done (energy used) = The (potential) energy gained by the load
The amount of work done by the electric hoist = 356,000 J
The mass of the load = 350.0 kg
The height to which the load is raised = h
The potential energy gained by the load = m×g×h = 350.0×9.81×h
356,000 J = 350.0×9.81×h
h = 356,000/(350.0*9.81) = 103.68 m
The height to which the load is lifted= 103.68 m
3) The initial potential energy of the roller coaster cart = 600*35.0*9.81 = 206010 J
The final potential energy = 600*28.0*9.81= 164808 J
The velocity at point 3 = 4.5 m/s
The kinetic energy at point 3 = 1/2*600*4.5^2 = 6075 J
The total energy at point 3 = 164808 + 6075 = 170,883 J
The energy loss = The initial potential energy at point 1 - Total energy at point 3
The energy loss = 206010 - 170,883 = 35,127 J
The heat energy due to friction that must have been produced between points 1 and 3 = 35,127 J
4) a. The heat energy absorbed = mass × specific heat capacity for water, [tex]C_{water}[/tex] × Temperature change
The mass of the water = 2.5×10² g = 0.25 kg
[tex]C_{water}[/tex] = 4,180 J/(kg·°C)
Initial temperature = 10.0°C
Final temperature = 95°C
The temperature change = 95.0°C - 10.0°C = 85.0°C
The heat energy absorbed = 0.25*4,180* 85 = 88,825 J = 88.825 kJ
(b) The percentage efficiency = (Heat absorbed/(Heat supplied)) × 100
The heat supplied = 543 kJ
The efficiency = (88.825/543) × 100 = 16.36 %
5) The mass of the box = 115 kg
Force acting on the rope = 255 N
The angle of inclination of the force to the horizontal = 24.5°
The distance the box is displaced = 15.0 m to the right
The work done = Force applied × distance moved in the direction of the force
The work done = Force applied × distance moved in the direction of the force
Given that the load moves a distance 15.0 m to the right,we have;
The component of the force acting in the direction of the movement of the load (to the right) is 225 × cos(24.5°) = 204.74 N
The work done = 204.7*15 = 3071.12 J
The amount of work done = 3,071.12 J
To a stationary observer, a bus moves south with a speed of 12 m/s. A man
inside walks toward the back of the bus with a speed of 0.5 m/s relative to
the bus. What is the velocity of the man according to a stationary observer?
A. 11 m/s south
B. 12.5 m/s south
C. 11.5 m/s south
D. 0.5 m/s south
ANSWER
C 11.5 m/s
EXPLANATION
Answer:
11.5m/s south
Explanation:
Online classes
Calculate the gravitational acceleration of a satellite that is in orbit at a distance of 1.0 x 10^8 meters from the center of the Earth (Mass of Earth is 6.0 × 10^24).
Answer:
[tex]g=0.035\ m/s^2[/tex]
Explanation:
Given that,
Mass of Earth, [tex]m=6\times 10^{24}\ kg[/tex]
We need to find the gravitational acceleration of a satellite that is in orbit at a distance of [tex]10^8\ m[/tex] from the center of the Earth.
Radius of earth is 6,371 km
The formula used to find the gravitational acceleration at a distance is given by :
[tex]g=\dfrac{Gm}{R^2}[/tex]
R = r+d
[tex]g=\dfrac{6.67\times 10^{-11}\times 6\times 10^{24}}{(10^8+6371\times 10^3)^2}\\\\g=0.035\ m/s^2[/tex]
So, the gravitational acceleration is [tex]0.035\ m/s^2[/tex].
What is the magnitude of the electrostatic force that the two protons inside the nucleus of a helium atom exert on each other? ( A distance of approximately r = 2*10–15 m separates the two protons.)
Answer:
F = 57.6 N
Explanation:
An electrostatic force is either a force of attraction or repulsion between two charges. When the two charges are like charges, the force is that of repulsion. But when they are of opposite charges, then the force between them is an attractive force.
A proton has a charge of 1.6 × [tex]10^{-19}[/tex] C. The electrostatic force can be determined by;
F = [tex]\frac{kq_{1}q_{2} }{r^{2} }[/tex]
Where: k is a constant, [tex]q_{1}[/tex] is the first charge, [tex]q_{2}[/tex] is the second charge, and r is the distance between the charges.
But, [tex]q_{1}[/tex] = [tex]q_{2}[/tex] = 1.6 × [tex]10^{-19}[/tex] C, k = 9 × [tex]10^{9}[/tex] N[tex]m^{2}[/tex]/[tex]C^{2}[/tex], r = 2 × [tex]10^{-15}[/tex] m. Therefore;
F = [tex]\frac{9*10^{9}*1.6*10^{-19} *1.6*10^{-19} }{(2*10^{-15}) ^{2} }[/tex]
= [tex]\frac{2.304*10^{-28} }{4*10^{-30} }[/tex]
= 57.6 N
The electrostatic force between the protons is 57.6 N.
A piano has a mass of 99 kg. What is the weight of the piano?
Explanation:
weight of the piano = mg
w = 99 x 10 =990 N
Click this link to view O*NET Skills section for Electrical Engineers. Note that common skills are listed toward the top and less common skills are listed toward the bottom. According to O*NET, what are some common skills Electrical Engineers need?
Explanation:
O*NET stands for Occupational Network and it is an online platform for job seekers around the world who are searching for jobs. This platforms provides the job information along with the required qualities, education background, skill sets, etc.
The most common skill sets that are required for an electrical engineers are
1. Analytical skills
2. Monitoring and active learning
3. Decision making
4. Able to manage the personal resources
5. Time management.
6. Should have knowledge about different software.
A light bulb lights up with a potential difference of 120 V and a current of 1.5 A. What is the energy consumption of the light bulb?
Power consumption = (voltage) x (current)
Power = (120 V) x (1.5 A)
Power = 180 watts
But 1 watt = 1 Joule/second
180 watts = 180 Joule/second
Energy consumption of the light bulb =
(180) x (number of seconds it's turned on) Joules
Which force acts on a body if it is fully or partially immersed in a
liquid?
Answer:
Buoyant Force
Explanation:
That's literally the definition of the buoyant force
sliding friction is _ than the static friction.
Answer:
less
Explanation:
Sliding friction is always less than static friction. This is because in sliding friction, the bodies slide with each other and thus the effect of friction is not more. However, it does not happen in the case of static friction.
Light travels 300 000 000 m/s and one year has approximately 32 000 000 second a light year is the distance light travels in one year
Explanation:
It is given that,
Speed of light, [tex]v=300 000 000\ m/s=3\times 10^8\ m/s[/tex]
Seconds in 1 year, [tex]t=32 000 000=32\times 10^6\ s[/tex]
We need to find the distance traveled by light in one year. Speed of an object is given by :
[tex]v=\dfrac{d}{t}[/tex]
So,
[tex]d=v\times t\\\\d=3\times 10^8\times 32\times 10^6\\\\d=9.6\times 10^{15}\ m[/tex]
Since,
[tex]1\ \text{light year}=9.46\times 10^{15}\ m\\\\1\ m=\dfrac{1}{9.46\times 10^{15}}\ \text{ly}\\\\9.6\times 10^{15}\ m=\dfrac{9.6\times 10^{15}}{9.46\times 10^{15}}\\\\d=1.01\ \text{ly}[/tex]
So, the distance covered by light is 1.01 light years.
The power source provides a current of 1.86 A at a potential difference of 3.90 V. Calculate the power of the power source. Use the equation:
power = potential difference × current
Choose the correct unit from the box below
C W J
Answer:
W
Explanation:
The unit for Power which is (Volt X Current) is Watts. and the symbol for Watts is W.
Hydrogen fuel cells are used on the space shuttle to provide the shuttle with all of its electrical energy. Explain why fuel cells are used instead of batteries.
Answer:
Hydrogen used in fuel cells has the energy to weight ratio ten times greater than lithium-ion batteries. Consequently, it offers much greater range while being lighter and occupying smaller volumes. It can also be recharged in a few minutes, similarly to gasoline vehicles.
Which egg floated higher? Why do you think that happened?
Answer:
Generally, fresh eggs will lie on the bottom of the bowl of water. Eggs that tilt so that the large end is up are older, and eggs that float are rotten.
Explanation:
When the current in a toroidal solenoid is changing at a rate of 0.0260 A/s, the magnitude of the induced emf is 12.2 mV. When the current equals 1.40 A, the average flux through each turn of the solenoid is 0.00308 Wb. How many turns does the solenoid have?
Answer:
The solenoid has 213 turns.
Explanation:
The number of the solenoid's turns (N) can be found as follows:
[tex] N = \frac{L*I}{\phi_{B}} [/tex] (1)
Where:
L: is the self-inductance of the solenoid
I: is the current = 1.40 A
[tex]\phi_{B}[/tex]: is the magnetic flux = 0.00308 Wb
The self-inductance of the solenoid (L) is:
[tex] L = \frac{|\epsilon|}{|dI/dt|} [/tex] (2)
Where:
ε: is the induced emf = 12.2x10⁻³ V
dI/dt: is the rate changing of the current = 0.0260 A/s
By entering equation (2) into (1) we can find the number of turns:
[tex] N = \frac{|\epsilon|*I}{\phi_{B}|dI/dt|} = \frac{12.2 \cdot 10^{-3} V*1.40 A}{0.00308 Wb*0.0260 A/s} = 213 [/tex]
Therefore, the solenoid has 213 turns.
I hope it helps you!
Is the following nuclear reaction balanced?
Answer:
yes
Explanation:
A rocket is launched vertically from the ground with an initial velocity of 64. Write a quadratic function that shows the height, in feet, of the rocket t seconds after it was launched.
Answer:
y = 64t − 16t²
Explanation:
y = y₀ + v₀ t + ½ at²
y = 0 + 64 t + ½ (-32) t²
y = 64t − 16t²
why is string a good force measurer?
Answer:
tension is how much force is being exerted on each end of the string, whereas length is how long the string is. So assuming that the string has finite mass, then the tension on the string should increase proportionally to the string according to Newton's law f=ma.
Explanation:
Which is one piece of evidence of seafloor spreading?
a. fossil material
b. continent material
c. drilled core samples
d. ocean water samples
Answer:
A. Continent material
Explanation:
Eruptions of molten material, which results in continent material is a piece of evidence of seafloor spreading.
Continent material is one piece of evidence of seafloor spreading. Option b is correct.
What is seafloor spreading?Seafloor spread is a phenomenon that happens along mid-ocean ridges, when new oceanic crust is generated by volcanic activity and then progressively travels away from the ridge.
The geological activity of seafloor spreading occurs when tectonic plates split apart.
Continent material is one piece of evidence of seafloor spreading.
Hence, option b is correct.
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Two children push on opposite sides of a door during play. Both push horizontally and perpendicular to the surface of the door. One child pushes with a force of 17.5 N at a distance of 0.59 m from the hinges, and the second child pushes at a distance of 0.47 m.
What force must the second child exert to keep the door from moving? Assume friction is negligible.
Answer:
F₂ = 21.97 N
Explanation:
this is a rotational equilibrium exercise, let's write the formula
∑ τ = 0
F₁ d₁ - F₂ d₂ = 0
force F₁ is 17.5 N and its distance d₁ = 0.59m, the distance d₂ = 0.47m
F₂ = F₁ d₁ / d₂
F₂ = 17.5 0.59 / 0.47
F₂ = 21.97 N
Three children use the same skateboard. i) 20-30kg, ii) 30-40 kg iii) 40-50kg Which child can move the skateboard using the smallest pushing force? Justify your choice.
Answer:
i) 20-30 kg
Explanation:
The child with the smallest mass range of 20-30 kg will require the smallest force to move his skate board because he/she has a smaller inertia force to overcome. The mass of a body is the measure of the inertia forces of the body. The inertia force makes it difficult for a body at rest to start moving, and a body already in motion to stop moving.
When the children try to move the skateboard, they exert a force that is proportional to the product of their mass and the acceleration with which they start moving. This force must exceed their body's inertia force before they would start moving.
from
F = ma
where F is the force required
m is the mass
a is the acceleration
We can see that for the given mass ranges, the children with the larger mass range will require more force in order to move their skateboard. Consequently, the child with the smallest mass range will require the smallest pushing force to move his skate board.
a skydiver jumped out of a plane and fell 9 miles to the ground. his average speed while falling was 174 miles/hour. how much time did the dive last?
Answer:
t = 0.051 seconds
Explanation:
Given that,
A skydiver jumped out of a plane and fell 9 miles to the ground. It means 9 miles is the distance covered.
The average speed of the skydiver is 174 miles/hour
We need to find the time for which he dive last. It means t is the time taken. Total distance covered divided by time taken is called average speed. So,
[tex]v=\dfrac{d}{t}\\\\t=\dfrac{d}{v}\\\\t=\dfrac{9}{174}\\\\t=0.051\ s[/tex]
So, a skydiver dive for 0.051 seconds.
Y=5sin (3x -4t)
Cdculate the wavelength frequency and period.
Pls answer and explanation with formula
explanation
the general form of wave equation is
y=Asin(kx-wt)
we have
y=5sin(3x-4t)
hence the angular frequency
w= 4s^-1
the frequency
f=w/2 pi
f=4/2 pi
f=4/2*3.14
f=0.64 hz
the period
T=1/f
T=1/0.64
T=1.5625=1.6
the wavelength
k=2 pi/lambda
lambda=2 pi/k
k=3
so
lambda=2*3.14/3
lambda=2.09
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A diver releases an air bubble of volume 3.0 cm3 from a depth of 18 m below the surface of a lake, where the temperature is 9.0 ∘C. Part A What is the volume of the bubble when it reaches just below the surface of the lake, where the temperature is 22 ∘C?
Answer:
Explanation:
We shall apply gas law formula to get the solution .
P₁ V₁ / T₁ = P₂ V₂ / T₂
P₁ = 10⁵ + 18 x 10³ x 9.8 where 10⁵ Pa is atmospheric pressure at surface
= 1.764 x 10⁵ + 10⁵
= 2.764 x 10⁵
2.764 x 10⁵ x 3 / ( 273 + 9 ) = 10⁵ x V₂ / ( 273 + 22 )
V₂ = 8.67 cm³
Which of the following does each different kind of atom represent?
O A. A nucleus
O B. An element
O C. An electron
OD. A neutron
Answer:
B
Explanation:
because atoms make up an element.
Answer:
B
Explanation:
it's b because an element makes up an atom and signifies the number of element in atom e.g (H2) the two signifies the number of atoms