Answer:
A) When the angle between the Force (F) and Displacement (x) is 0°, because, Work done (W) is directly proportional to the Cosine of the Angle between the Force applied and the resultant displacement of the subject.
W = F•x cos ∅
If ∅ = 0°,
W = F•x ===> Maximum Work Done.
If ∅ = 45°,
W = F•x/√2
If ∅ = 90°,
W = 0
If ∅ = 180°,
W = –F•x ===> Minimum Work Done.
Determine a differential equation for the velocity v(t) of a falling body of mass m if air resistance is proportional to the square of the instantaneous velocity. Assume the downward direction is positive. (Use k > 0 for the constant of proportionality, g > 0 for acceleration due to gravity, and v for v(t).)
A freely falling mass m will be pulled down toward the ground with downward acceleration +g while feeling upward drag D due to air resistance with acceleration -a such that D = - m a = - k v ². Hence the body's velocity v(t) changes with respect to time t according to the differential equation,
dv(t)/dt = m g - k v ²
The driver of a 1000 kg car traveling on the interstate at 35 m/s slams on his brakes to avoid hitting a second vehicle in front of him, which had come to rest because of congestion ahead. After the brakes are applied, a constant friction force of 800 N acts on the car. Ignore air resistance, at what minimum distance should the brakes be applied to avoid collision with the other vehicle
Answer:
765.625 m
Explanation:
When brakes are applied , work is done by frictional force to reduce the kinetic energy of the car . To stop the car , the work done by brake must equalize the kinetic energy of car .
1/2 m v² = F d
m is mass of the car , v its velocity , F is frictional force and d is displacement of car .
1/2 x 1000 x 35² = 800 x d
d = 765.625 m
1. the position of a particles moving on a straight line is given by X =12 + 18t + 9t^2meter
(a) find the instantaneous veloctiy at
t=5s [dx/dt=v]
Answer:
v = 108 m/s.
Explanation:
Given that,
The position of a particle moving on a straight line is given by :
[tex]X =12 + 18t + 9t^2[/tex]
We need to find the instantaneous velocity at t=5s.
Velocity, [tex]v=\dfrac{dX}{dt}[/tex]
So,
[tex]v=\dfrac{d(12 + 18t + 9t^2)}{dt}\\\\=18+18t[/tex]
Instantaneous velocity at t = 5 s will be :
v = 18+18t
v = 18+18(5)
= 18 + 90
= 108 m/s
So, the instantaneous veloctiy at t=5s is 108 m/s.
1
A boy pulls his toy on a smooth horizontal
surface with a rope inclined at 60° to the
horizontal. If the effective force pulling the toy
along the horizontal surface is 5 N, calculate
the tension in the rope:
A 2.50 N B 4.33 N C 5.00 N
D 8.66 N E 10.0 N.
(SC/GCE)
Answer: wqcjn qefveqeqfbj qeib
Explanation:oiaer vgneiofrvn eiforbnewtjbioe
On Earth a gallon of milk has the same mass as a gallon of milk in space, but it has a different __________.
A.
weight
B.
inertia
C.
amount of matter
D.
volume
Answer:
A. Weight
Explanation:
On Earth a gallon of milk has the same mass as a gallon of milk in space, but it has a different weight
Which ray diagram demonstrates the phenomenon of absorption?
Answer:
B
Explanation:
The ray diagram demonstrated the phenomenon of absorption in B. Hence, option B is correct.
What is absorption?Absorption is the phenomenon of electromagnetic radiation taking up the energy of photons and it also transfers the electromagnetic energy to the internal energy of the absorber.
Absorption refers to the transfer of the energy of a wave to matter as the wave passes through it. The process in which the light waves get converted into energy. Absorption causes attenuation of the waves and the intensity decreases gradually when the light waves propagate through the medium.
From the given, the first diagram represents the light passes through the slit, it gets diffracted and forms alternate bright and dark fringes in the screen. The third diagram represents that the light ray strikes the surface it gets reflected and the path of light gets changed.
Thus, the absorption is the ray diagram given in the second image. Hence, option B is correct.
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3 A picture is supported by two vertical strings; if the weighi
of the picture is 50 N what is the force exerted by each
string ?
Answer:
The force exerted by each string is 25 N
Explanation:
Net Force
The net force is the vector sum of forces acting on a body. The net force is a single force that represents the effect of the original forces on the body's motion. It gives the particle the same acceleration as all those actual forces together as described by Newton's second law of motion.
The picture described in the problem is hanging at rest supported by two vertical strings. This means that the net force acting on it is zero.
Assume the magnitude of each of these equal forces is F, and the picture has a weight of W=50 N, thus the net force is:
F + F - W
The positive signs indicate an upwards direction and the negative sign means a downwards direction. Since the net force is zero:
F + F - W = 0
2F = W
F = W/2 = 50 N/2
F = 25 N
The force exerted by each string is 25 N
A hockey player is standing on his skates on a frozen pond when an opposing player, moving with a uniform speed of 4.0 m/s, skates by with the puck. After 2.80 s, the first player makes up his mind to chase his opponent. If he accelerates uniformly at 0.14 m/s2, determine each of the following:
a. How long does it take him to catch his opponent?
b. How far has he traveled in that time?
Answer:
a)[tex]t=59.817652833125294s \approx 59.8s[/tex]
b)[tex]D_1=894.01m[/tex]
Explanation:
From the question we are told that
Speed of opposing player [tex]V_2=4.0m/s[/tex]
First player chase his opponent after[tex]t=2.80t[/tex]
Acceleration of first player [tex]a=0.14 m/s2[/tex]
Let time of catch be [tex]t_c[/tex]
a)Generally the Equation for distance covered is mathematically given as follows
Distance to catch First opponent
[tex]D_1=\frac{1}{2}(0.14)t^2[/tex]
[tex]D_1=0.07t^2[/tex]
Distance to covered Second opponent
[tex]D_2=(2.8+t)*4[/tex]
Generally when first opponent catch the second opponent it is represented mathematically as
[tex]D_2=D_1[/tex]
[tex]0.07t^2=(2.8+t)*4[/tex]
[tex]0.07t^2=11.2+4t[/tex]
[tex]0.07t^2-4t-11.2[/tex]
[tex]t=59.817652833125294s \approx 59.8s[/tex]
b)Generally the the total time traveled by the first opponent is mathematically given as
[tex]D_1=\frac{t^2}{4}[/tex]
[tex]D_1=\frac{59.8^2}{4}[/tex]
[tex]D_1=894.01m[/tex]
Determine the small gravitational force F which the copper sphere exerts on the steel sphere. Both spheres are homogeneous, and the value of r is 65 mm. Express your result as a vector.
Answer:
[tex]F=3.665 \times 10^{-7} N[/tex] acting along the line joining both the sphere and always attractive in nature.
Explanation:
The given radius of both the sphere, r= 65 mm = 0.065 m
So, the volume of the spheres, [tex]v= \frac 4 3 \pi r^3[/tex]
[tex]v= \frac 4 3 \pi (0.065)^3 = 1.150 \times 10^{-3} m^3[/tex]
The density of steel, [tex]\rho _s = 7850 kg/m^3[/tex]
and the density of copper, [tex]\rho_c= 8940 kg/m^3[/tex]
Let M be the mass of the copper ball and m is the mass of the steel ball.
So, [tex]M=\rho_c v= 8940\times 1.150 \times 10^{-3} = 10.281[/tex] kg
[tex]m=\rho_s v= 7850\times 1.150 \times 10^{-3} = 9.0275[/tex] kg
The gravitational force, F, between the two objects having masses M and m and separated by distance d is
[tex]F=\frac{GMm}{d^2}[/tex]
Where [tex]G= 6.674 30 x 10^{-11} m^3 kg^{-1} s^{-2}[/tex] is the universal gravitational constant.
When both the sphere touches each other, d = 2r= 2 x 0.065 = 0.13 m
Hence, the gravitational force between both the sphere,
[tex]F= \frac {6.674 30 x 10^{-11}\times 10.281 \times 9.0275}{0.13^2} \\\\F=3.665 \times 10^{-7} N[/tex]
The nature of gravitational force is always attractive and acting along the line joining the center of both the sphere.
with which of the following is the weak nuclear force associated
a 13-gram bullet, moving at 270 m/s, penetrates a 2 kg block of wood and emerges at a speed of 130 m/s. if teh block sits one a fricitonless surface, find its velocity after the bullet emerges.
Answer:
1.52m/s
Explanation:
Using the law of conservation of momentum
m1u1 + m2u2 = (m1+m2)v
m1 and m2 are the masses
u1 and u2 are the initial velocities
v is the final velocity
Substitute the given values into the formula
0.013(270)+2(130) = (270+130)v
3.51+260 = 400v
263.51 = 400v
v = 400/263.51
v = 1.52m/s
Hence the velocity after the bullet emerges is 1.52m/s
What happens to the molecules of a substance when it changes phase?
When it comes to phase shifts or phase change the greater the intermolecular interactions are the closer the molecules are to one another.
What is phase change?A phase change occurs when matter transitions from one state to another (solid, liquid, gas, plasma). When enough energy is provided to the system (or when a significant quantity is removed), as well as when the pressure on the system is adjusted, these changes occur.Any two phases of matter can undergo phase transitions.All phase shifts are accompanied by an energy shift.Isothermal phase shifts occur in all cases.Temperature changes can cause substances to change phase often. Most substances are solid at low temperatures; as the temperature rises, they become liquid; and at even higher temperatures, they become gaseous.To Know more about Phase change here
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Question 3 of 10
An engine performs 6400 J of work on a motorbike. The motorbike and rider
have a combined mass of 200 kg. If the bike started at rest, what is the speed
of the bike after the work is performed?
Answer:
8 m/s
Explanation:
KE Formula: KE = 1/2mv^2
Kinetic Energy is equal to energy, J.
6400 = 1/2 * 200 * V^2
1/2 * 200 = 100
6400 = 100 * V^2
6400/100 = V^2
64 = V^2
Square root both sides
Speed is 8 m/s
Which of the following is NOT a characteristic of noble gases? *
very reactive
colorless
odorless
unreactive
You decide to do an experiment to investigate Newton's Third Law. Below are several
example experiments you might run to help investigate your questions. Which one of the
following examples below are not related to Newton’s Third Law?
A. You and a friend push on each other’s hands while wearing roller blades and
observe the force of the shove.
B. You set a ball on the ground and observe the force of gravity on the ball
C. You stand on the bathroom scale and then decide to jump off and observe the
change in the reading.
D. You drive a remote-controlled car and observe the force at work
Answer:
C
Explanation:
You stand on the bathroom scale and then decide to jump off and observe the
change in the reading.
all igneous rock forms from cooling lava, but not all of them look the same, (ex: some have large crystals) why is that:
a. lava cooled BENEATH the surface and SLOWLY allows large crystals to develop bc they have more time to grow in size.
b. lava cooled ABOVE the surface which SLOWLY allows large crystals to develop bc they have more time to grow in size.
c. lava cooled BENEATH the surface and QUICKLY allows large crystals to develop bc they have more time to grow in size.
D. lava cooled ABOVE the surface which QUICKLY allows large crystals to develop bc they have more time to grow in size.
Answer:
b
Explanation:
A young athlete has a mass of 42 kg. On a day when there is no wind she runs a 100m race in 14.2
Answer:
7 m/s approx
Explanation:
Step one:
Given data
Mass m= 42kg
distance covered= 100m
time taken = 14.2 seconds
Required
The speed of the athlete
Step two:
We know that speed= distance/time
Substitute
Speed= 100/14.2
Speed= 7.04 m/s
Speed= 7 m/s approx
A 365-kg car traveling horizontally at 21.1 m/sec slams into a tree and comes to a halt in 0.22 seconds. What force did the tree exert on the car to stop it?
please show work
Explanation:
Remember Newton's Second law
[tex]F = ma[/tex]
We can use this to solve for the force exerted by the tree on the car when it stops the car.
We aren't given the acceleration directly in the problem statement, but we can solve for acceleration.
Recall that acceleration is the change is velocity per unit time. [tex]a = \frac{\Delta v}{\Delta t}[/tex]
We know the original velocity as 21.1 m/s and the final velocity as 0.0 m/s. The time that it takes to stop the car is 0.22 seconds.
Now we can solve using the equation. [tex]F = \frac{21.1 - 0.0}{0.22} * 365[/tex]
need help asap.......................
Answer:
vt3bryhtevy4g24vu5hy4
What would happen if the Earth stopped rotating?
Answer:
the atmosphere would still be in motion with the Earth's original 1100 mile per hour rotation speed at the equator. ... This means rocks, topsoil, trees, buildings, your pet dog, and so on, would be swept away into the atmosphere.
Explanation:
to me, this means we would proabaly be sucked into outer space and could die if no astronaut gear is on
50 j of work was performed in 20 seconds. How much power was used to preform this task
Answer:
Power = 2.5 [W]
Explanation:
To be able to solve this problem we must remember that power is defined as the relationship of the work done in a given time interval.
[tex]P=W/t[/tex]
where:
P = power [W] (units of watts)
W = work = 50 [J]
t = time = 20 [s]
Now replacing:
[tex]P=50/20\\P=2.5[W][/tex]
Answer:
2.5
Explanation:
Find the required answer to the following by substituting the numbers. (Bonus points for knowing the units). PLEASE ANSWER
a) Using Fnet = ma, what is Fnet if m = 13.2kg and a = 10ms^-2?
b) Using I = P/V, what is I if V = 15V and P = 75W
Answer:
a) F=ma
F=13.2×10
F=132
b) I=P/V
I=75/15
I=5
An object's center of mass is _______. Select all that apply. An object's center of mass is _______. Select all that apply. the point about which the net torque is zero the point about which an unconstrained rotation occurs the geometric center of the object the mass-weighted center of the object the point about which the angular momentum is zero Previous AnswersRequest Answer Incorrect; Try Again; 7 attempts remaining
Answer:
the point about which an unconstrained rotation occurs
the mass-weighted center of the object
Explanation:
The center of mass of an object can be described to be a a position that is defined relative to the object
The center of mass is the average position of every parts of the object. At this point we can assume that all of the mass of this object is concentrated
When weighted according to their masses, the center of mass is the average position of all the parts of the object. While other points in this object are rotating around it, the center of mass would not rotate (fixed).
So the correct options are:
1. the point about which an unconstrained rotation occurs
2. the mass-weighted center of the object
Answer: The correct option is
the point about which an unconstrained rotation occurs
Explanation:
The CENTER OF MASS is the average position of the different parts of the the object system which are weighted base on their masses
What may result when the energy that builds up at plate boundaries is released because the plates suddenly overcome the force of friction?
volcano
hot spot
earthquake
trench
Which of the following is a pure substance?
Calculate the increase in the internal energy when 1000 g of boiling water at 212° F is converted into steam at the same
temperature. Atmospheric pressure is 1.013 X 10 Pa and the latent heat of vaporization is 2.260 MJ kg
-1
Answer:
The increase in the internal energy is 1.840 x 10⁶ J.
Explanation:
Given;
mass of the water, m = 1000 g = 1 kg
temperature of the boiling water, t = 212 ° F = 100 ° C
latent heat of vaporization, L = 2.260 MJ/kg = 2.260 x 10⁶ J/kg
The internal energy of the boiling water is calculated as;
Q₁ = mcΔθ
where;
c is specific heat capacity of water, = 4200 J/kg.⁰C
Δθ is change in temperature = 100 ° C
Q₁ = 1 x 4200 x 100
Q₁ = 420,000 J
The internal energy of the vaporized steam is calculated as;
Q₂ = mL
Q₂ = 1 x 2.260 x 10⁶
Q₂ = 2,260,000 J
The increase in the internal energy is calculated as;
ΔQ = Q₂ - Q₁
ΔQ = 2,260,000 J - 420,000 J
ΔQ = 1,840,000 J
ΔQ = 1.840 x 10⁶ J
Therefore, the increase in the internal energy is 1.840 x 10⁶ J.
Which observation is the best evidence that some colors of visible light are
being absorbed in this photo?
A. The man's head is distorted under the water.
B. The top of the man's head appears disconnected.
C. The shape of the man's arm is clearly seen underwater.
D. The snorkel in the man's mouth appears yellow.
Answer:
id say D
Explanation:
because its the only answer that has to do with colors and visable light
but A and B also have to do with eachother so i feel like it could be with one of those but it def isnt C
I am sorry if i am wrong, let me know tho!
Answer:
A.
Explanation:
Why solar panels are usually painted black
Answer:
The silicon used to make monocrystalline solar cells has a high level of purity. ... Because of the way light interacts with a monocrystalline silicon layer, monocrystalline solar panels appear black in color.
A 0.11 N m torque is applied to a fan that was initially at rest. The fan has moment of inertia of 0.034 kg m2. Determine the kinetic energy of the fan after 8.0 s.
Answer:
2.72*10-3 Joules
Explanation:
From Newton's second law of motion
F=ma
[tex]\tau=I*\alpha[/tex]
given
[tex]\tau= 0.11Nm\\\\I=0.034kgm^2\\\\t= 8s\\\\\alpha=?[/tex]
[tex]\alpha =0.11/0.034\\\\\alpha=3.23 rad/s^2[/tex]
the angular velocity is
[tex]\omega = \alpha/t\\\\\omega =3.23/8\\\\\omega =0.4 rad/s[/tex]
[tex]KE= 1/2*I* \omega^2[/tex]
[tex]KE=1/2*0.034*0.4^2\\\\KE=1/2*0.034*0.16\\\\KE=0.00272\\\\KE=2.72*10^-3J[/tex]
Suppose the entire population of the world gathers in one spot and, at the sounding of a prearranged signal, everyone jumps up. While all the people are in the air, does Earth gain momentum in the opposite direction?
a) No; the inertial mass of Earth is so large that the planet’s change in motion is imperceptible.
b) Yes; because of its much larger inertial mass, however, the change in momentum of Earth is much less than that of all the jumping people.
c) Yes; Earth recoils, like a rifle firing a bullet, with a change in momentum equal to and opposite that of the people.
d) It depends.
Answer:(B)
Explanation:
No; the inertial mass of Earth is so large that the planet’s change in motion is imperceptible, therefore the correct answer is option A.
What is Newton's first law?According to Newton's first law, until pushed to alter its condition by the intervention of an external force, every object will continue to be at rest or in uniform motion along a single direction.
As given in the problem suppose the entire population of the world gathers in one spot and, at the sound of a prearranged signal, everyone jumps up. While all the people are in the air, we have to find out if Earth gains momentum in the opposite direction,
The mass of the earth is very huge approximately 5.97 ×10²⁴ kilogram.
Even the combined mass of all the population combined would be negligible as compared to the mass of the earth.
Thus, the earth would not gain momentum in the opposite direction.
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