Answer:
a) Wapp = 520 N
b) ΔUf = 447 N
c) Wn = 0
d) Wg = 0
e) ΔK = 73 J
f) v = 1.96 m/s
Explanation:
a)
Applying the definition of work, as the dot product between the applied force and the displacement, since both are parallel each other, the work done on the box by the applied force can be written as follows:[tex]W_{app} = F_{app} * \Delta X = 130 N * 4.0 m = 520 N (1)[/tex]
b)
The change in the internal energy due to the friction, is numerically equal to the work done by the force of friction.This work is just the product of the kinetic force of friction, times the displacement, times the cosine of the angle between them.As the friction force opposes to the displacement, we can find the work done by this force as follows:[tex]W_{ffr} = F_{fr} * \Delta X * cos (180) (2)[/tex]
The kinetic force of friction, can be expressed as the product of the kinetic coefficient of friction times the normal force.If the surface is level, this normal force is equal to the weight of the object, so we can write (2), as follows:[tex]W_{ffr} = F_{fr} * \Delta X * cos (180) = -\mu_{k} * m* g* \Delta X = \\ -0.300*38.0kg9.8 m/s2*4.0m = -447 J (3)[/tex]
So, the increase in the internal energy in the box-floor system due to the friction, is -Wffr = 447 Jc)
Since the normal force (by definition) is normal to the surface, and the displacement is parallel to the surface, no work is done by the normal force.d)
Since the surface is level, the displacement is parallel to it, and the gravitational force is always downward, we conclude that no work is done by the gravitational force either.e)
The work-energy theorem says that the net work done on the object, must be equal to the change in kinetic energy.We have two forces causing net work, the applied force, and the friction force.So the change in kinetic energy must be equal to the sum of the work done by both forces, that we found in a) and b).So, we can write the following expression:[tex]\Delta K = W_{app} + W_{ffr} = 520 J - 447 J = 73 J (4)[/tex]
f)
Since the object starts at rest, the change in kinetic energy that we got in e) is just the value of the final kinetic energy.So, replacing in (4), we finally get:[tex]\Delta K = 73 J = \frac{1}{2}*m*v^{2} (5)[/tex]
Solving for v:[tex]v_{f} = \sqrt{\frac{2*\Delta K}{m} } = \sqrt{\frac{2*73J}{38.0kg}} = 1.96 m/s (6)[/tex]a) The work done by the applied force [tex]W_{AP}=520\ J[/tex]
b) The change in the internal energy [tex]\Delta U=447\ J[/tex]
c) Work done by normal force [tex]W_n=0[/tex]
d) Work done by gravitation [tex]W_g=0[/tex]
e) The change in KE will be [tex]\Delta KE=73\ J[/tex]
f) The final speed v = 1.96 m/s
What will be the work done?The work done on any object can be defined as the force applied on the object and its displacement due the effect of the force.
If the object achieve movement due to the work then the energy in the object will be kinetic energy.
If the object attains some height against the gravity then the energy in the object will be potential energy.
Now it is given in the question that
The horizontal force [tex]F_h=130\N[/tex]
mass of the object m= 38 kg
Coefficient of friction [tex]\mu=0.3[/tex]
Displacement of the object [tex]\delta x=4\ m[/tex]
(a) The work done will be
[tex]W=F_h\tines \Delta x[/tex]
[tex]W=130\times 4=520\ J[/tex]
(b) The increase in the internal energy
The increase in the internal energy of the box is due to the energy generated by the force of friction so
[tex]W_f=F_f\times \Delta x\times Cos(180)[/tex]
here [tex]F_f[/tex] is the frictional force and is given as
[tex]\mu=\dfrac{F_f}{R}[/tex]
Here R is the normal reaction and its value will be weight of the box in opposite direction.
[tex]\mu=\dfrac{F_f}{-mg}[/tex]
[tex]F_f=-mg\times \mu[/tex]
[tex]W_f=F_f\times \Delta x\times Cos180=-mg\times\mu \times cos180[/tex]
[tex]W_f=-38\times 9.81\times 0.3\times4=-447\J\ J[/tex]
(c) The work done by the normal force will be zero because the displacement is horizontal against the normal work so the work done will be zero.
(d) The work done by the gravitational force will also be zero. Because the displacement is horizontal and the gravitational force acts downward.
(e) The change in the KE of the box.
The change in the KE of the box will be the net energy of the box so from the work energy theorem the net energy will be
[tex]\Delta KE =W_{AP}-W_f=520-447=73\ J[/tex]
(f) The speed of the box
The KE of the box will be
[tex]KE=\dfrac{1}{2} mv^2[/tex]
[tex]v=\sqrt{ \dfrac{2\times KE}{m}[/tex]
[tex]v=\sqrt{\dfrac{2\times73}{38} }=1.96\ \dfrac{m}{s}[/tex]
Thus
a) The work done by the applied force [tex]W_{AP}=520\ J[/tex]
b) The change in the internal energy [tex]\Delta U=447\ J[/tex]
c) Work done by normal force [tex]W_n=0[/tex]
d) Work done by gravitation [tex]W_g=0[/tex]
e) The change in KE will be [tex]\Delta KE=73\ J[/tex]
f) The final speed v = 1.96 m/s
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A 416 kg merry-go-round in the shape of a horizontal disk with a radius of 1.7 m is set in motion by wrapping a rope about the rim of the disk and pulling on the rope. How large a torque would have to be exerted to bring the merry-go-round from rest to an angular speed of 3.7 rad/s in 2.9 s
Answer:
The torque exerted on the merry-go-round is 766.95 Nm
Explanation:
Given;
mass of the merry-go-round, m = 416 kg
radius of the disk, r = 1.7 m
angular speed of the merry-go-round, ω = 3.7 rad/s
time of motion, t = 2.9 s
The torque exerted on the merry-go-round is calculated as;
[tex]\tau = Fr= I\alpha\\\\\tau = (\frac{1}{2} m r^2)(\frac{\omega }{t} )\\\\\tau = (\frac{1}{2} \times 416 \times 1.7^2)( \frac{3.7}{2.9} )\\\\\tau = 766.95 \ Nm[/tex]
Therefore, the torque exerted on the merry-go-round is 766.95 Nm
A basketball was thrown and reached a velocity of 3 m/s in 0.5 seconds. What was the acceleration of the basketball?
Answer: acceleration is 6 m/s²
Explanation: V = vo + at. If initial speed Is zero,
V = at and a= V/t = 3m/s /0.5 s
Select the correct answer.
Which graph shows the correct relationship between kinetic energy and speed?
Answer:
c
Explanation:
It's c the last one u see
A fisherman notices that his boat is moving up and down periodically without any horizontal motion, owing to waves on the surface of the water. It takes a time of 2.60 s for the boat to travel from its highest point to its lowest, a total distance of 0.700 m . The fisherman sees that the wave crests are spaced a horizontal distance of 6.00 m apart.
Required:
a. How fast are the waves traveling?
b. What is the amplitude of each wave?
c. If the total vertical distance traveled by the boat were 0.500 , but the other data remained the same, how fast are the waves traveling?
d. If the total vertical distance traveled by the boat were 0.500 , but the other data remained the same, what is the amplitude of each wave?
Answer:
a) 1.2 m/s
b) 0.350 m
c) 1.2 m/s
d) 0.250 m
Explanation:
a)
At any traveling wave, there exists a fixed relationship between the frequency, the speed and the wavelength, as follows:[tex]v = \lambda * f (1)[/tex]
We know that the frequency is equal to the number of cycles that the wave does in a second, so it's the inverse of the time needed to complete one cycle, that we call the period.In our case, since the wave completes one half cycle (from the highest point to the lowest one) in 2.60 s, this means that the time needed to complete a cycle, is just the double of it, i.e., 5.20 s .The frequency of the wave is just the inverse of this value:⇒ f = 1/T = 1/5.20 s = 0.2 1/s = 0.2 Hz (2)If the wave crests are spaced a horizontal distance of 6.0 m apart, this means that the wavelength λ is just 6.0 m.Replacing in (1) by (2) and the given λ, we can find the speed v, as follows:[tex]v = \lambda * f = 6.0 m * 0.2 1/s = 1.2 m/s (3)[/tex]
b)
By definition, the amplitude of the wave, is the absolute value of its highest value over its the zero reference level (in this case the surface of the water), so it is the half of the total vertical distance traveled by the boat:⇒ A = Δd/2 = 0.700m/2 = 0.350 m (4)
c)
Since the amplitude of the wave is independent of the frequency and the wavelength (that define the speed of the wave) the wave speed remains the same, i.e., 1.2 m/s.d)
If the total distance traveled by the boat were 0.500 m , the amplitude would be just half this value, as follows:⇒ A = Δd/2 = 0.500m/2 = 0.250 m (5)find acceleration for force 2N acting on 2 Kg?
Answer:
1 m/s^2
Explanation:
F=ma
2 Newtons=2 Kg * a
a=1 m/s^2
What are some possible factors that can be the X
and Y axis of a motion graph?
Answer:
x-Speed/velocity
y-time.
Explanation:
because Speed is a rate of change of distance while time how long it takes a a car to move to a specific point
ASAP Even though the force exerted on each object in a collision is the same strength, if the objects have different masses, their will be different. * O changes in velocity O amount of force O speed and direction
Answer:
it should be changes in velocity
Explanation:
I hope this helps!
A physicist drives through a stop light. When he is pulled over, he tells the police officer that the Doppler shift made the red light of wavelength 635 nm appear green to him, with a wavelength of 550 nm. The police officer writes out a traffic citation for speeding. How fast was the physicist traveling, according to his own testimony
Answer:
Explanation:
[tex]\lambda[/tex] = Observed wavelength = 550 nm
[tex]\lambda'[/tex] = Actual wavelength = 635 nm
c = Speed of light = [tex]3\times 10^8\ \text{m/s}[/tex]
v = Velocity of the physicist
Doppler shift is given by
[tex]f=\sqrt{\dfrac{c+v}{c-v}}f'\\\Rightarrow \dfrac{c}{\lambda}=\sqrt{\dfrac{c+v}{c-v}}\dfrac{c}{\lambda'}\\\Rightarrow \dfrac{\lambda'^2}{\lambda^2}=\dfrac{c+v}{c-v}\\\Rightarrow \dfrac{\lambda'^2}{\lambda^2}=\dfrac{1+\dfrac{v}{c}}{1-\dfrac{v}{c}}\\\Rightarrow \dfrac{\lambda'^2}{\lambda^2}(1-\dfrac{v}{c})=1+\dfrac{v}{c}\\\Rightarrow \dfrac{\lambda'^2}{\lambda^2}(1-\dfrac{v}{c})=1+\dfrac{v}{c}\\\Rightarrow \dfrac{\lambda'^2}{\lambda^2}-1=\dfrac{v}{c}(1+\dfrac{\lambda'^2}{\lambda^2})\\\Rightarrow v=\dfrac{c(\dfrac{\lambda'^2}{\lambda^2}-1)}{1+\dfrac{\lambda'^2}{\lambda^2}}[/tex]
[tex]\Rightarrow v=\dfrac{3\times 10^8\times (\dfrac{635^2}{550^2}-1)}{1+\dfrac{635^2}{550^2}}\\\Rightarrow v=42817669.77\ \text{m/s}[/tex]
The physicist was traveling at a velocity of [tex]42817669.77\ \text{m/s}[/tex].
A 430 kg motorcycle starts from rest and accelerates to a speed of 12 m/s.
Calculate the net work done on the motorcycle.
a. 42 kJ
b. 31 kJ
c. 38 kJ
d. 35 kJ
e. none of these
Answer:
Vi = 0
Vf = 12 m/s
ΔV = Vf - Vi
ΔV = 12 m/s
Change in kinetic energy
ΔKE = Kf - Ki
ΔKE = 1/2 mv^2 - 0
ΔKE = 1/2 * 430 kg * (12 m/s)^2
ΔKE = 30,960
ΔKE = 30,960 joules
Work = ΔK
Work = 30,960 J
a boy standing by a lake sees a fish in the pond and tries to thrust a spear into it he will success or not explain with reason
He will not probably success to thrust a spear into the fish in the pond because when light travels from water to air , it bends due to refractive property of light.
What is refraction of light?Refraction is the bending of a wave as it travels through different media. The two materials' different densities are what lead to the bending.
Refraction is defined as "the change in a wave's direction as it passes through a medium."
Although light refraction is one of the most frequently seen phenomena, refraction can also occur with sound and water waves. We can use optical tools like lenses, prisms, and magnifying glasses thanks to refraction. We can focus light on our retina because of the refraction of light, which is another benefit.
When light travels from water to air , it bends due to refractive property of light. So, he e will not probably success to thrust a spear into the fish.
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Calculate the kinetic energy of an 80,000 kg airplane that is flying with a velocity of 167 m/s.
Answer:
1115560000 J
Explanation:
1/2 * 80,000 * 167^2 m/s = 1115560000 J
On the Moon's surface, lunar astronauts placed a corner reflector, off which a laser beam is periodically reflected. The distance to the Moon is calculated from the round-trip time. The Earth's atmosphere slows down light. Assume the distance to the Moon is precisely 3.84×108 m, and Earth's atmosphere (which varies in density with altitude) is equivalent to a layer 30.0 km thick with a constant index of refraction n=1.000293. What is the difference in travel time for light that travels only through space to the moon and back and light that travels through the atmosphere and space?
Answer:
a) space only t = 1.28 s
b) space+ atmosphere t_ {total} = 1.28000003 s
Explanation:
The speed of light in each material medium is constant, which is why we can use the uniform motion relations
v= x / t
a) let's look for time when it only travels through space
t = x / c
t = 3.84 10⁸/3 10⁸
t = 1.28 s
b) we look for time when it travels part in space and part in the atmosphere
space
as it indicates that the atmosphere has a thickness of e = 30 10³ m
t₁ = (D-e) / c
t₁ = (3.84 10⁸ - 30.0 10³) / 3 10⁸
t₁ = 1.2799 s
atmosphere
we use the refractive index
n = c / v
v = c / n
we substitute in the equation of time
t₂ = e n / c
t₂ = 30 10³ 1,000293 /3 10⁸
t₂ = 1.000293 10⁻⁴ s
therefore the total travel time is
t_ {total} = t₁ + t₂
t_ {total} = 1.2799+ 1.000293 10⁻⁴
t_ {total} = 1.28000003 s
we can see that the time increase due to the atmosphere is very small
A ball is sitting at the top of a ramp. As the ball rolls down the ramp, the potential energy of the ball decreases, what happens to the potential energy as the ball moves
Answer:
the potential energy decreases as it is converted to kinetic energy.
Explanation:
As things move, their potential energy converts to kinetic energy to power them along. When a ball rolls down the top of a ramp, all the potential energy it accumulated at the top of the ramp converts to kinetic energy to help it roll down. In other words, its potential energy decreases as its kinetic energy increases.
a pendulum clock having Copper keeps time at 20 degree Celsius it gains 15 second per day if cooled to 0°C celsius calculate the coefficient of linear expansion of copper.
?.............................
which causes magnets to stick to metal
Answer:
Steel
Explanation:
Steel is a metal that magnets stick to because iron can be found inside steel
Answer:Magnets stick to any metal that contains iron, cobalt or nickel.
Explanation:Iron is found in steel, so steel attracts a magnet and sticks to it. Stainless steel, however, does not attract a magnet.
Steel beams are used for load bearing supports in a building. Each beam is 4.0 m long with a cross-sectional area of 7.5 10-3 m2 and supports a load of 4.5 104 N. Young's modulus for steel is 210 ✕ 109 N/m2.
A motorcycle traveling due east at a constant speed covers 75 kilometers in
1.5 hours. What is its velocity in km/h?
Answer:
The velocity of the motorcycle is 50km/hr due east.
How much work is done when 100 N of force is applied to a rock to move it 20 m
Answer: 2000 J
Explanation: work W = F s
Please help me!!!!!!
Answer:
Gamma ray will get to the Earth first due to his frequency of transmission
What is the only difference between the reactant and product side of a chemical reaction?
Answer:
Products is the result. Reactants produce the result
Explanation:
,,
Find the momentum of a 15 kg object traveling at 7 m/s
What is the momentum
What is the velocity
What is the mass
What equation did you use to solve?
Find the momentum of a 15 kg object traveling at 7 m/s.
The momentum of an object is found by using the following formula:
[tex]\displaystyle p=mv[/tex]
P is the momentum and is measured in kg · m/sm is the mass and is measured in kgv is the velocity and is measured in m/sIn this question, the object is 15 kg and is travelling at 7 m/s. That means the mass is 15 kg and the velocity is 7 m/s.
Since all the needed variables are found, substitute it into the equation:
[tex]\displaystyle p=mv \rightarrow p=15 \times 7[/tex]
Multiply:
[tex]\displaystyle p=105\ kg \times m/s[/tex]
__________________________________________________________
What is the momentum? 105 kg · m/s
What is the velocity? 7 m/s
What is the mass? 15 kg
What equation did you use to solve? p = mv
__________________________________________________________
A reaction occurs when a compound breaks down. This reaction has one reactant and two or more products. Energy, as from a battery, is usually needed to break the compound apart.
Answer:
decomposition
Explanation:
Car B is rounding the curve with a constant speed of 54 km/h, and car A is approaching car B in the intersection with a constant speed of 72 km/h. The x-y axes are attached to car B. The distance separating the two cars at the instant depicted is 40 m. Determine:
This question is incomplete, the complete question is;
Car B is rounding the curve with a constant speed of 54 km/h, and car A is approaching car B in the intersection with a constant speed of 72 km/h. The x-y axes are attached to car B. The distance separating the two cars at the instant depicted is 40 m. Determine: the angular velocity of Bxy rotating frame (ω).
Answer:
the angular velocity of Bxy rotating frame (ω) is 0.15 rad/s
Explanation:
Given the data in the question and image below and as illustrated in the second image;
distance S = 40 m
V[tex]_B[/tex] = 54 km/hr
V[tex]_A[/tex] = 72 km/hr
α = 100 m
now, angular velocity of Bxy will be;
ω[tex]_B[/tex] = V[tex]_B[/tex] / α
so, we substitute
ω[tex]_B[/tex] = ( 54 × 1000/3600) / 100
ω[tex]_B[/tex] = 15 / 100
ω[tex]_B[/tex] = 0.15 rad/s
Therefore, the angular velocity of Bxy rotating frame (ω) is 0.15 rad/s
Why was Mars orbiter sent to mars?
Explanation:
to develop the technologies required for designing, planning, management and operations of an interplanetary mission. The secondary objective is to explore Mars' surface features, morphology, mineralogy and Martian atmosphere using indigenous scientific instruments
Answer: Mars Climate Orbiter was lost on arrival September 23, 1999. Engineers concluded that the spacecraft entered the planet's atmosphere too low and probably burned up.
Explanation: The scientific reasons for going to Mars can be summarised by the search for life, understanding the surface and the planet's evolution, and preparing for future human exploration. Understanding whether life existed elsewhere in the Universe beyond Earth is a fundamental question of humankind.
starting from rest, your bicycle can reach a speed of 4.0 m/s in 50 s. Assuming that your bicycle accelerates at a constant rate, what is its acceleration?
Answer:
0.08 ms^-2
Explanation:
by using v= u + at
initial velocity is zero as it is starting from rest
4= 0 + a x 50
4/50 = a = 0.08 ms^-2
A cryogenic vacuum pump works by condensing vapors onto some absorbent medium. This is an efficient and clean way to pump a system in a research environment. The term cryo means cold, which indicates that these types of vacuum pumps contain a refrigerant cycle to cool the internal parts. The temperature difference between the inside and outside of a typical cryogenic pump is Δ=303 ∘C . Derive an expression to convert this difference into Fahrenheit and express the answer.
Answer: Temperature in Fahrenheit is 577.4
Explanation:
The conversion factor for converting celcius to Fahrenheit is:
[tex]F=\frac{9}{5}\times C+32[/tex]
where F = temperature in Fahrenheit
C = Temperature in Celcius
Given : Temperature difference in Celcius = [tex]303^0C[/tex]
Putting in the values we get:
[tex]F=\frac{9}{5}\times 303+32[/tex]
[tex]F=577.4[/tex]
Thus the answer in Fahrenheit is 577.4
The required conversion of temperature from Celsius to Fahrenheit is 577.4 Degree Fahrenheit.
Given data:
The temperature difference between the inside and outside of a typical cryogenic pump is, [tex]\Delta T=303^{\circ}\rm C[/tex].
The degree measure of the flow of heat from one point to another is known as the temperature at a specific point. The temperature measurements are done in Celsius, Fahrenheit and Kelvin scales. The expression to convert the Celsius scale to Fahrenheit scale is,
[tex]T=(C \times \dfrac{9}{5} + 32)\;\rm ^{\circ}F[/tex]
Solving as,
[tex]T=(303 \times \dfrac{9}{5}+32 )\;\rm ^{\circ}F\\\\T=(303 \times \dfrac{9}{5}+32 )\;\rm ^{\circ}F\\\\T=577.4\;\rm ^{\circ}F[/tex]
Thus, we can conclude that the required conversion of temperature from Celsius to Fahrenheit is 577.4 Degree Fahrenheit.
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it takes 560s for a runner to complete one circular lap, moving at a speed of 6.00 m/s. what is the radius of a track?
Answer:
534.8 meters
Explanation:
Use T=(2*pi*r)/v
560=(2*pi*r)/6
3360=2*pi*r
1680=pi*r
534.8 meters=radius
It takes 560s for a runner to complete one circular lap, moving at a speed of 6.00 m/s. The radius of a track is 534.7 m.
What is Distance?The distance covered by a body is equal to the sum of total path covered. It is equal to the total path traveled by an object during its entire journey.This quantity is always positive. It can't be 0 or a negative number.It is defined as a scalar quantity.
Mathematically, it can be calculated as follows :
distance = speed × time
The formula relating distance (d), speed (s), and time (t) is
d = st
First, Calculating the distance,
d = 560 s × 6 m·s⁻¹
= 3360 m
When, Calculating the track radius,
The distance travelled is the circumference of a circle,
C = 2пr
r = 3360/2п
= 534.7 m
The radius of the track is 534.7 m.
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A girl weighing 45kg is standing on the floor, exerting a downward force of 200N on the floor. The force exerted on her by the floor is ..............
Select one:
a.
No force exerted
b.
Less than 2000N
c.
Equal to 200 N
d.
Greater than 200 N
Answer:
c.
Equal to 200 N..........
Which of the following best describes gravitational potential energy,
O The energy stored in an object when you lift it,
O The energy stored in an object due to its chemical structure,
The energy of an object in motion.
The energy stored in an object due to its electric charges.
According to Newton's first law, an object at rest will _____.
never move
stay at rest forever
start moving
stay at rest unless moved by force