Answer:
a. 0.41 m
b. 5.72 m/s
c. i. For part (a), I chose the hand as the reference level since the penny was thrown from the hand and the height of the penny at the hand is zero and also, it is easier to calculate from a zero reference level.
ii. For part (b), I chose the ground as the reference level since the height of the penny above the ground is positive and the height of the penny when the penny hits the ground is zero and also, it is easier to calculate from a zero reference level.
d. 5.72 m/s
Explanation:
a. Use energy to find how high the penny goes above your hand before stopping.
Taking the hand as the ground level, and from the law of conservation of energy, the total mechanical energy at the hand, E equals the total mechanical energy when the penny stops in the air, E'.
E = E'
U + K = U' + K' where U = initial potential energy at hand level = mgh where h = height at hand level = 0, K = initial kinetic energy at hand level = 1/2mv² where v = speed at hand level = 2.85 m/s, U' = final potential energy at stopping level = mgh' where h' = height at stopping level, K = final kinetic energy at stopping level = 1/2mv'² where v = speed at stopping level = 0 m/s (since the penny momentarily stops)
So, U + K = U' + K'
mgh + 1/2mv² = mgh' + 1/2mv'²
substituting the values of the variables into the equation, we have
mg(0) + 1/2m(2.85 m/s)² = mgh' + 1/2m(0 m/s)²
0 + 1/2m(8.1225 m²/s²) = mgh' + 0
m(4.06125 m²/s²) = mgh'
h' = 4.06125 m²/s² ÷ g
h' = 4.06125 m²/s² ÷ 9.8 m/s²
h' = 0.41 m
(b) The penny then falls to the floor, 1.26 m below your hand. Use energy to find its speed just before it hits the floor.
Taking the hand as the ground level, and from the law of conservation of energy, the total mechanical energy when the penny stops in the air, E' equals the total mechanical energy on the ground, E"
E' = E"
U' + K' = U" + K" where U' = initial potential energy at stopping level = mgh" where h' = height at stopping level = height of penny above hand, h' + height of hand above ground = 0.41 m + 1.26 m = 1.67 m, K = initial kinetic energy at stopping level = 1/2mv'² where v = speed at stopping level = 0 m/s (since the penny momentarily stops), U = final potential energy at ground level = mgh₁ where h₁ = height at ground level = 0, K = final kinetic energy at ground level = 1/2mv"² where v" = speed at ground level,
So, U' + K' = U' + K'
mgh" + 1/2mv'² = mgh₁ + 1/2mv"²
substituting the values of the variables into the equation, we have
mg(1.67 m) + 1/2m(0 m/s)² = mg(0) + 1/2mv"²
1.67mg + 0 = 0 + 1/2mv"²
1.67mg = 1/2mv"²
1.67g = 1/2v"²
v"² = 2(1.67g)
v" = √[2(1.67g)]
v" = √[2(1.67 m × 9.8 m/s²)]
v" = √[2(16.366 m²/s²)]
v" = √[32.732 m²/s²)]
v" = 5.72 m/s
(c) Explain your choice of reference level for parts (a) and (b).
i. For part (a), I chose the hand as the reference level since the penny was thrown from the hand and the height of the penny at the hand is zero and also, it is easier to calculate from a zero reference level.
ii. For part (b), I chose the ground as the reference level since the height of the penny above the ground is positive and the height of the penny when the penny hits the ground is zero and also, it is easier to calculate from a zero reference level.
(d) Choose a different reference level and repeat part (b)
Taking the hand as the ground level, and from the law of conservation of energy, the total mechanical energy when the penny stops in the air, E' equals the total mechanical energy on the ground, E"
E' = E"
U' + K' = U" + K" where U' = initial potential energy at stopping level = mgh' where h' = height at stopping level = 0.41 m, K = initial kinetic energy at stopping level = 1/2mv'² where v' = speed at stopping level = 0 m/s (since the penny momentarily stops), U = final potential energy at ground level = mgh₁ where h₂ = height of hand above the ground level = height of ground below hand = -1.26 m(it is negative since the ground is below the hand), K = final kinetic energy at ground level = 1/2mv"² where v = speed at ground level,
So, U' + K' = U' + K'
mgh' + 1/2mv'² = mgh₂ + 1/2mv"²
substituting the values of the variables into the equation, we have
mg(0.41 m) + 1/2m(0 m/s)² = mg(-1.26 m) + 1/2mv"²
0.41mg + 0 = -1.26 mg + 1/2mv"²
0.41mg + 1.26mg = 1/2mv"²
1.67mg = 1/2mv"²
1.67g = 1/2v"²
v"² = 2(1.67g)
v" = √[2(1.67g)]
v" = √[2(1.67 m × 9.8 m/s²)]
v" = √[2(16.366 m²/s²)]
v" = √[32.732 m²/s²)]
v" = 5.72 m/s
b) A stone floor feels very cold to bare feet in winter, but a carpet in
the same room feels comfortably warm. Why is this?
Answer:
A stone floor feels very cold to bare feet in winter, but a carpet in the same room feels comfortably warm.This is because both the floor and the carpet have the same temperature as both are exposed to the same atmosphere. But the former conducts away the heat from the feet better than the carpet as the latter is a non-conductor. So the feet losing more heat, the floor appears cooler to the feet
Explanation:
Hope it may help you!!
Both actually have same temperature. Our feet are warm. Floor is conductor of heat while carpet is not. When we walk on floor, then floor takes away or conducts the heat from our feet, so we feel cold. While carpet doesn't do that, so we feel warm.
Ball X has a mass of 8kg and is moving toward ball Y (which is sitting still) at 2m/s. After they collide, ball X is
sitting still. How fast is ball Y moving after the collision if it has a mass of 4kg?
Answer:
v = 4 m/s
Explanation:
Given :
Ball X :
Mass, m1 = 8kg ;
Initial Velocity, u1 = 2 m/s
Final velocity, v1 = 0
Ball Y:
Mass, m2 = 4kg ;
Initial Velocity, u2 = 0 m/s
Final velocity, v2 = v
(m1u1 + m2u2) = (m2v2 + m1v1)
(8*2 + 4*0) = (4*v + 4*0)
16 + 0 = 4v + 0
16 = 4v
v = 16 / 4
v = 4 m/s
Answer:
Explanation:
This is the Law of Momentum Conservation which for us looks like this:
[tex][m_xv_x+m_yv_y]_b=[m_xv_x+m_yv_y]_a[/tex] and that should look familiar to you if this is what you are doing in physics. Filling in our particular info:
[(8.0 × 2.0)+ (4.0 × 0.0)] = [(8.0 × 0.0) + (4.0v)] and
16 + 0 = 0 + 4.0v and
16 = 4.0v so
v = 4.0 in the direction of ball X
1. The electromagnetic spectrum is the range of all types of radiation.
a. index of refraction
b. EM
c. laser
Answer:
EM
Explanation:
The index of refraction is a special property that shows how light travels through different medias. It does not concern itself with the spectrum, only what it will do to that spectrum under laboratory conditions.
Laser light is a very narrow concentrated light form. It is not the entire spectrum, but only a very small part of it.
The answer you want is EM Electromagnetic Radiation
(x – 2)² = 5(y + 1), where x and y are measured in centimeters. You need to place a new light bulb in your flashlight. How far away from the vertex of the parabolic mirror should you place the bulb to ensure a perfect beam of light? The bulb should be placed .
Answer:
The coordinates of the point the bulb should be placed is (2, 0.25)
Explanation:
The given equation of a parabola is presented as follows;
(x - 2)² = 5·(y + 1)
The point the bulb should be placed is the focus of the parabolic mirror to ensure a perfect (straight) beam
The general form of the equation of a parabola is (x - h)² = 4·p·(y - k)
The coordinates of the focus of the parabola for p > 0 f = (h, k + p)
By comparison, h = 2, k = -1, and p = 5/4
∴ The coordinates of the focus of the parabola, f = (2, -1 + 5/4) = (2, 0.25)
The coordinates of the point the bulb should be placed is at the focus, f = (2, 0.25).
Spending more time with her grandchildren is most likely a short-term goal
for a person of which of these ages?
A. 20 years old
B. 10 years old
C. 30 years old
D. 60 years old
Answer:60
Explanation:
The drone can fly for 25 minutes before the battery needs recharging.
The power output of the battery is 65.0 W
Calculate the maximum energy stored by the battery.
Answer:
105.6 KJ
Answer
3.7/5
4
hope this will help you friend.
what is meant by fundamental unit? write any two difference between mass and weight.
Answer:
Fundamental unit is any unit that is not dependent on other units and other units can be derived from them
Explanation:
Units such as Kilogram, Mass and Time are said to be fundamental units because they are independent.
Differences between Mass and weight;
1. Mass is the measure of the amount of matter in a body while weight is a measure of how the force of gravity acts upon that mass.
2. Mass is a scalar quantity while weight is a vector quantity
A room has a rectangular shape of 4000 mom by 3600mm according to the architecture plan It is supposed to be fitted with tiles which are square in shape and size of 12 cm. How many tiles are required to cover the entire floor
Explanation:
First find the area of the entire floor:
Area of a rectangle= length × width
( 4000mm× 3600mm)
14400000mm²
Area of one square tile??= side ×side
12cm×12cm
144cm²
Convert cm to mm
1cm²=100mm²
144cm²=144cm²/1cm²×100mm²
=14,400mm²
Number of tiles required to cover the entire floor= 14400000mm²/14400mm²
=1000
calculate the voltage applied to 2.00
Answer:
Here is your answer
Explanation:
1.55 V is the answer
hope u like it
"" damped force equation ""
Answer:
In many vibrating systems the frictional force Ff can be modeled as being proportional to the velocity v of the object: Ff = −cv, where c is called the viscous damping coefficient.
with respect to air the refractive index of ice is 1.31 and that of rock salt is 1.54 calculate the refractive index of rock salt with respect to ice
Answer:
1.17
Explanation:
Given that,
The refractive index of ice wrt air = 1.31
The refractive index of rock salt wrt air = 1.54
We need to find the refractive index of rock salt with respect to ice.
We know that,
refractive index = (speed of light in air or vaccum)/( speed of light in that medium)
So,
The speed of light in ice = c/(1.31)
The speed of light in rock salt = c/(1.54)
So, the refractive index of rock salt with respect to ice is :
[tex]\mu=\dfrac{1.54}{1.31}\\\\=1.17[/tex]
So, the required refractive index of rock salt wrt ice is 1.17.
when is the acceleration of body is positive negative and zero?
Answer:
【 In vector form , if angle between velocity vector and acceleration vector is less than 90° and greater than 0° then it is positive acceleration and if it is less than 180° and greater than 90° then it is negative acceleration. If there is no acceleration vector then it is called zero acceleration. 】
PLEASEE HELPP!!!
Describe melting.
Describe evaporation.
Describe boiling.
Describe condensation.
Describe freezing.
Melting: the substance changes back from the solid to the liquid
Evaporation: the process by which water changed from a liquid to a gas.
Boiling: the process by which a liquid turns into a vapor when it is heated to it's boiling point.
Condensation: the substance changed from a gas to a liquid
Freezing: the substance changed from a liquid to solid.
Answer:
Melting is a process that causes a substance to change from a solid to a liquid.
Evaporation is the process of turning from liquid into vapour.
Boiling is the rapid vaporization of a liquid, which occurs when a liquid is heated to its boiling point, the
Condensation is the process of water vapor turning back into liquid water
Freezing is a phase transition where a liquid turns into a solid when its temperature is lowered below its freezing point
the ratio of the energy per second radiated by the filament of a lamp at 250k to that radiated at 2000k, assuming the filament is a blackbody radiator? The filament of a particular electric lamp can be considered as a 90%blackbody radiator. calculate the energy per second radiated when its temperature is 2000k if its surface area is 10∧-6 m²
Answer:
(a) [tex]\frac{P_{250k}}{P_{2000k}}=2.4\ x\ 10^{-4}[/tex]
(b) P = 0.816 Watt
Explanation:
(a)
The power radiated from a black body is given by Stefan Boltzman Law:
[tex]P = \sigma AT^4[/tex]
where,
P = Energy Radiated per Second = ?
σ = stefan boltzman constant = 5.67 x 10⁻⁸ W/m².K⁴
T = Absolute Temperature
So the ratio of power at 250 K to the power at 2000 K is given as:
[tex]\frac{P_{250k}}{P_{2000k}}=\frac{\sigma A(250)^4}{\sigma A(2000)^4}\\\\\frac{P_{250k}}{P_{2000k}}=2.4\ x\ 10^{-4}[/tex]
(b)
Now, for 90% radiator blackbody at 2000 K:
[tex]P = (0.9)(5.67\ x\ 10^{-8}\ W/m^2.K^4)(1\ x\ 10^{-6}\ m^2)(2000\ K)^4[/tex]
P = 0.816 Watt
Select the correct answer.
Which quantity is a vector quantity?
ОА. .
acceleration
OB.
mass
OC.
speed
O D.
volume
Reset
Next
Answer:
acceleration is the vector quantity because it depends on particular direction and has magnitude
Match the reactants with the products. zinc sulfate + copper aluminum chloride + copper copper oxide copper + water copper sulfate + oxygen
Answer:
The Reactants Products
Copper sulfate + zinc → Zinc sulfate + copper
aluminum + copper chloride → Aluminum chloride + Copper
Copper + Oxygen → Copper oxide
Explanation:
The Reactants Products
Copper sulfate + zinc Zinc sulfate + copper
aluminum + copper chloride Aluminum chloride + Copper
Copper + Oxygen Copper oxide
First reaction can be described as a single replacement reaction
Second reaction is also a single replacement reaction just like the first reaction
The third is a synthesis reaction ( i.e. reaction in which elements combine to form single compound )
Accelaration is a derived quantity .Give reason
Answer:
The accerlation is a derived from the other quantities like change in velocity/time take etc.
Two tuning forks, 492 Hz and 498 Hz, are struck simultaneously. How many beats will be heard?
none
2.00 beats
4.00 beats
6.00 beats
Answer:
6 beats
If one fork beats once and another twice in the same time period
you would hear 1 beat. (Same for 2 and 3 beats).
Señalar la importancia de las capacidades fisico-motiz que se desarrollan en el futbol de salon y dar un ejemplo para cada uno
La respuesta correcta para esta pregunta abierta es la siguiente.
A pesar de que no anexas opciones o incisos para responder, podemos comentar lo siguiente.
La importancia de las capacidades físico-motriz que se desarrollan en el futbol de salón son determinantes para desarrollar o maximizar las actividades propias de este deporte con objeto de rendir al máximo y aspirar al mejor de los resultados.
Estas capacidades físico-motrices son las que le permiten a un jugador realizar su máximo esfuerzo, mejorar su desempeño físico y conseguir resultados positivos.
Estamos hablando de la fuerza, la velocidad y la resistencia.
La velocidad es la aceleración que el jugador de futbol necesita para aumentar su velocidad de un punto A, a un punto B, en el menor tiempo posible.
La resistencia es la capacidad del jugador de futbol para mantener ese nivel de aceleración y desempeño, sin bajar su rendimiento. Su capacidad física debe ser resistente para ser constante en su rendimiento físico.
La fuerza es la potencia con la que desempeña los movimiento físicos dentro de la cancha.
A HIGH SPEED TRAIN IS 180M LONG AND IT IS TRAVELLING AT 50M/S.HOW LONG WILL IT TAKE TO PASS A PERSON STANDING AT A LEVEL CROSSING?
B-HOW LONG WILL IT TAKE TO PASS COMPLETELY THROUGH A STATION WHOSE PLATFORMS ARE 220M IN LENGTH?
Answer:
a. Time = 3.6 seconds
b. Time = 4.4 seconds
Explanation:
Given the following data;
Distance = 180 m
Speed = 50 m/s
a. To find the time;
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 time the subject of formula, we have;
[tex]Time = \frac{distance}{speed}[/tex]
Substituting into the equation, we have;
[tex]Time = \frac{180}{50}[/tex]
Time = 3.6 seconds
b. Distance = 220 meters
Speed = 50 m/s
To find the time;
[tex]Time = \frac{distance}{speed}[/tex]
Substituting into the equation, we have;
[tex]Time = \frac{220}{50}[/tex]
Time = 4.4 seconds
A constant unbalanced force is applied to an object for a period of time. What will happen to the objects acceleration?
a. It will accelerate in the direction of the net force.
b. It will accelerate opposite the direction net force.
c. There is no acceleration.
d. Not enough information to answer
Answer:
A
Explanation:
The moving object will accelerate as long as a net force is applied. If a net force is not applied, the object will continue to move at a constant speed along the same path in curved spacetime (due to gravity). If the net force continues the velocity of the object will continue to increase until nearly reaching the limit (speed of light).
I need help answer these questions please
Answer:
1. 25 J
2. 250 J
3. 900,000 J
4. 7,500 J
Explanation:
1. The distance the wheelbarrow is tilted, d = 0.5 m
The force used to tilt the wheelbarrow, F = 50 N
The work done, W = F × d
∴ W = 50 N × 0.5 m = 25 J
2. Work done, W = Force × Distance
The applied force, F = 50 N
The distance the sand is moved, d = 5 m
∴ W = 50 N × 5 m = 250 J
3. The work done, W = The load lifted × The height to which the load is lifted
∴ W = 90,000 N × 10 m = 900,000 J
The work done, W = 900,000 J
4. The work output of the skateboard = The work input × Efficiency
Given that the skateboard is an ideal machine, we have;
The work output of the skateboard = The work input = W
W = F × d
F = 15 N, d = 500 m
∴ W = 15 N × 500 m = 7,500 J
The work output of the skateboard = W = 7,500 J.
A ball is dropped from the top of a building. It initially
moves at 40 m/s. After 0.5 seconds, it moves at 3.8
m/s.
What force is responsible for the slowing of the ball?
air resistance
gravity
normal
tension
Answer:
Explanation:
I'm assuming you missed the decimal point in the initial velocity and that it should be 4.0 m/s. If after a half of a second it is moving a tiny bit slower, it would be because of air resistance. You can only neglect air resistance if the problems you are doing tell you neglect it.
Answer:
Air resistance
Explanation:
I got it correct on the quiz :)
pleaase help me i don't know this !!!
Answer:
coefficient=1.09N/m×g
coefficient=1.09N/0.413g×10m/s square
coefficient=1.09N/4.13N
coefficent=0.263
f= uK
here f is force, u is cofficient of friction , k is normal force
k = mg
f = umg
1.09 = u × 0.41 × 10
u = 1.09 ÷ 4.1
u = 0.26
Object A has twice the mass of object B. Both objects are moving at the same speed. Which accurately describes how inertia relates to Newton’s second law of motion in this example? Object A has twice the mass of object B. Both objects are moving at the same speed.
A. Object A requires twice the force to stop as Object B.
B. Object A requires one-and-a-half times the force to stop as Object B.
C. Object A requires four times the force to stop as Object B.
Answer:
A. Object A requires twice the force to stop as Object B.
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.
Newton's Second Law of Motion states that the acceleration of a physical object is directly proportional to the net force acting on the physical object and inversely proportional to its mass.
Mathematically, it is given by the formula;
[tex] Acceleration = \frac {Net \; force}{mass} [/tex]
Let's assume the following values;
Mass of object B = 10 kg
Mass of object A = 2 * B = 2 * 10 = 20 kg
Acceleration = 5 m/s²
I. To find the force for B;
[tex] Force = mass * acceleration [/tex]
[tex] Force = 10 * 5 [/tex]
Force B = 50 Newton
II. To find the force for A;
[tex] Force = mass * acceleration [/tex]
[tex] Force = 20 * 5 [/tex]
Force A = 100 Newton
From the calculation, we can deduce that Force A (100 N) is twice or double the value of Force B (50 N).
In conclusion, since object A has twice the mass of object B and both objects are moving at the same speed, object A would require twice the force to stop as Object B.
Which has greater kinetic energy, a car traveling at 40 mph or a half-as-massive car traveling at 80 mph?
a
-The 40 mph car
-The 80 mph car
-Both have the same kinetic energy
-Neither has kinetic energy
Answer:
The 80 mph car
Because the formula says 1/2 mass but for the velocity it is squared
The circuit diagram below shows the locations of four switches. Which
switch configuration creates a short circuit?
fo
W
WT
Answer:
C option
Explanation:
Hope this helps... pls vote as brainliest
quicklime which is calcium oxide, is made by heathig limestone in a furnace as per the equation :
CaCO3(s)CaO(s)+CO2
7.00Kg of calcium oxide was formed. what mass of calcium carbonate was heated?
Answer:
h2 PRD algo trata gevbjjgcvnkoytewxc.
Answer:
12.5kg
Explanation:
The process is explained in the paper
a student drops a ball off the top of building and records that the ball takes 3.32s to reach the ground (g=9.8 m/s^2). what is the ball's speed just before hitting the ground?
Answer:
Explanation:
Use the one-dimensional equation for motion
v = v₀ + at and filling in,
v = 0 + (-9.8)(3.32) so
v = -33 m/s (negative because it is going downwards and upwards is positive).
A car starts from rest. if rhe final velocity becomes 50m /s after 10 second calculate the acceleration of the car.
Answer:5m/s² well I am not pretty sure but hope it's help
Explanation:
u=0m
final velocity ,v=50m/s
t=10s
(v-u)/t=(50-0)/10=50/10=5m/s²
