Answer:
The velocity at that time would be [tex](-67.975\; \rm s)[/tex]. The velocity of this particle is continuously changing.
Explanation:
Differentiate the expression for position [tex]x[/tex] with respect to time [tex]t[/tex] to find an expression for velocity.
[tex]\begin{aligned}v(t) &= \frac{d}{dt}[x(t)] \\ &= \frac{d}{dt} \left[ 7.4 + 9.2\, t - 2.1\, t^{3}\right]\\ &= 9.2 - 6.3\, t^{2}\end{aligned}[/tex].
Hence, at [tex]t = 3.5\; \rm s[/tex], velocity would be [tex]v(3.5) = 9.2 - 6.3 \times (3.5)^{2} = -67.975\; \rm m[/tex].
Since velocity [tex]v(t)[/tex] changes with time [tex]t[/tex], the velocity of this particle is continuously changing.
A bullet with a mass mb=13.5 g is fired into a block of wood at velocity vb=245 m/s. The block is attached to a spring that has a spring constant k of 205 N/m. The block and bullet continue to move, compressing the spring by 35.0 cm before the whole system momentarily comes to a stop. Assuming that the surface on which the block is resting is frictionless, determine the mass mw of the wooden block.
Momentum is conserved, so the sum of the momenta of the bullet and block before collision is equal to the momentum of the combined bullet-block system,
[tex]m_bv_b+m_wv_w = (m_b+m_w)v[/tex]
where v is the speed of the bullet-block system. The block starts at rest so it has no initial momentum, and solving for v gives
[tex]v = \dfrac{m_b}{m_b+m_w} v_b[/tex]
The total work W performed by the spring on the bullet-block system as it is compressed a distance x is
[tex]W = -\dfrac12kx^2[/tex]
where k is the spring constant, and the work done is negative because the restoring force of the spring opposes the bullet-block as it compresses the spring.
By the work-energy theorem, the total work done is equal to the change in the bullet-block's kinetic energy ∆K, so we have
[tex]W_{\rm total} = W = \Delta K[/tex]
The bullet-block starts moving with velocity v found earlier and comes to a stop as the spring slows it down, so we have
[tex]-\dfrac12kx^2 = -\dfrac12(m_b+m_w)v^2 \implies kx^2 = \dfrac{{m_b}^2}{m_b+m_w}{v_b}^2[/tex]
Solve for [tex]m_w[/tex]:
[tex]m_w=\dfrac1k\left(\dfrac{m_bv_b}x\right)^2-m_b[/tex]
[tex]m_w=\dfrac1{205\frac{\rm N}{\rm m}}\left(\dfrac{(0.0135\,\mathrm{kg})\left(245\frac{\rm m}{\rm s}\right)}{0.350\,\rm m}\right)^2-0.0135\,\mathrm{kg}\approx \boxed{0.422\,\mathrm{kg}}[/tex]
How many atoms are in the compound NaNO3?
Explanation:
3 atoms are in the compound
Un muelle se alarga 20 cm cuando ejercemos sobre él una fuerza de 24 N. Calcula:El valor de la constante elástica del muelle
Answer:
120 Nm-1
Explanation:
Según la ley de Hooke;
F = Ke
F = fuerza sobre el resorte
K = constante de fuerza
e = extensión
Por eso;
K = F / e
K = 24N / 20 × 10 ^ -2m
K = 120 Nm-1
What do you mean by unit?
Unit is the quantity of a constant magnitude which is used to measure the magnitudes of other quantities of the same nature.
Answer:
The standard known quantity which is used to measure a physical quantities is known as unit.
Kgms-1-= Ns ...solution
Answer:
units of impact or impulse or momnetum are same
These are
Kg m s-1 or N s
A rabbit runs a distance of 60 meters in 20s. What is the average speed?
Answer:
3 m/s
Explanation:
Given,
Total distance = 60 m
Total time = 20 s
We know that,
Average speed = Total distance/Total time
=> Average speed = 60 m/20 s
=> Average speed = 3 m/1 s
=> Average speed = 3 m/s
Average speed=Total distance/Total time
[tex]\\ \sf\longmapsto Average\:Speed=\dfrac{60}{20}[/tex]
[tex]\\ \sf\longmapsto Average\:Speed=3m/s[/tex]
How do longshore currents shape the land?
Answer:
Longshore drift has a very powerful influence on the shape and composition of the coastline. It changes the slopes of beaches and creates long, narrow shoals of land called spits, that extend out from shore. Longshore drift may also create or destroy entire “barrier islands” along a shoreline.
How does the temperature of a planet determine the states of matter you would observe on that planet?
Explanation:
the temperature will determine the kinetic energy or degree of freedom of the molecules of matter.
if the temperature is high, the kinetic energy of the molecules increase which may cause a change of state into a gas which has molecules of high kinetic energy. this shows that temperature is a measure of the kinetic energy of the molecules.
An observer measures a 100 Hz Doppler shift as an ambulance goes by. At rest, the frequency of the ambulance's siren is 2,000 Hz. What is the speed of the ambulance?
The change in the frequency of the sound, due to the relative motion of the source of sound and the observer, is determined by the Doppler's Effect.
The speed of the ambulance (source) is "6517 m/s"
The equation of Doppler's Effect is given as follows:
[tex]f_o = \frac{v+v_o}{v+v_s}f_s[/tex]
where,
[tex]f_o\\[/tex] = frequency of sound measure by observer = 100 Hz
v = speed of sound = 343 m/s
[tex]v_o[/tex] = speed of observer = 0 m/s
[tex]v_s[/tex] = speed of ambulance (source) = ?
[tex]f_s[/tex] = actual frequency = 2000 Hz
Therefore, using the values, we get:
[tex]100\ Hz = \frac{343\ m/s + 0\ m/s}{343\ m/s + v_s}(2000\ Hz)\\\\(100\ Hz)(343\ m/s + v_s) = (343\ m/s)(2000\ Hz)\\\\v_s = \frac{686000\ Hz.m/s - 34300\ Hz.m/s}{100\ Hz}[/tex]
v_s = 6517 m/s
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What is the purpose of the lab the importance of the topic and the question you are trying to answer?
perpose of lab is to store apparatus and do some experiment
Helps someone to know the exert lengh of something
Describe the laws of liquid pressure and explain the term fluid. (Please try to give the correct answer 'coz it's urgent!)
Answer:
The laws of liquid pressure are: ... The liquid pressure at a point inside the liquid is same in all directions. The liquid pressure at a point inside the liquid is directly proportional to the depth of that point from the free surface of liquid. The pressure of liquid at same depth is different for different liquids
Answer:
The laws of liquid pressure:
The pressure that is inside the liquid rises with the intensity from the surface of a liquid.
The term fluid:
Fluid is basically liquid and a substance that is known to have no certain shape. The opposite of the term fluid would be solid.
the hydrometer with the density of liquid to be 800 kg metre per square is the volume of the submerged part of the hydrometer is 5 into 10 to the power minus 5 calculate the mass of the hydrometer
Answer:
Mass = 0.04 Kg
Explanation:
Given the following data;
Density = 800 kg/m³
Volume = 5 * 10^{-5} m³
To find the mass of the object;
Density can be defined as mass all over the volume of an object.
Simply stated, density is mass per unit volume of an object.
Mathematically, density is given by the formula;
[tex] Density = \frac {mass}{volume} [/tex]
Making mass the subject of formula, we have;
[tex] Mass = density * volume [/tex]
Substituting the values into the formula, we have;
[tex] Mass = 800 * 5 * 10^{-5} [/tex]
Mass = 0.04 Kg
If we aim a radio telescope at a distant spiral arm of the Milky Way Galaxy, we will probably observe a 21-cm line. If we point a large optical telescope at this same region, we will probably not be able to detect the neutral hydrogen that gives rise to the 21-cm radio signal. Why not
Answer:
Because of the interstellar dust and interior location of the solar system.
Explanation:
We will probably not be able to detect the neutral hydrogen that gives rise to the 21-cm radio signal if we point a large optical telescope to the region because, the interstellar dust obscures the location of the spiral arm of the Milky way galaxy and this makes neutral hydrogen that gives rise to the 21-cm radio signal difficult to detect.
Also, the interior location of the solar system also makes the neutral hydrogen that gives rise to the 21-cm radio signal difficult to detect.
So, the interstellar dust and the interior location of the solar system makes it difficult to detect the neutral hydrogen that gives rise to the 21-cm radio signal with a large optical telescope.
A converging lens of focal length 20cm, forms a real image twice the size of the object. Calculate:
i) the power of the lens;
ii) the position of the image.
Answer:
Solition given:
focal length(f)=20cm
size of image(v)=2x
size of object(u)=x
we have
power of lens= reciprocal to focal length=1/20=0.05/cm
ii.
the position of the image is beyond C.
Explanation:
See the attachment !!!!!!!
State newton's universal law of gravitation
Every particle of mass is attracted to every other particle of mass. The magnitude of the force between two objects is proportional to the product of their masses, and inversely proportional to the square of the distance between them. The direction of the force is along the line between their centers.
(NOTE: Newton's 3rd law of motion tells us that gravitational forces always come in pairs. Between two objects, there are two forces ... one in each direction. Their strengths are equal ... Your weight on Earth is exactly equal to the Earth's weight on YOU.)
define Neutons 3rd law .
Answer:
that when two object interact, they apply forces to one another that are equal in magnitude and opposite in direction.
Explanation:
Newton's third law: the law of action and reaction
Using deductive reasoning, write the converse, inverse, and contra positive of an if-then statement. Part I: Write an if-then statement below. (1 point)
Converse:
if q , then p
Inverse:
If not p , the not q.
Contra Positive:
If not q, then not p.
If then statement is a conditional statement. In this statement there is some condition at the first part of the sentence and then in the second part there is a conclusion.
The example of if then sentence is as follows,
If this camel is thirsty, then it will drink water from the well.
In this example there is a condition in first part that if camel is thirsty, in the second part there is conclusion which states that then it will drink water from well.
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In a simple machine the energy input is 120J if the efficiency of the machine is 80% calculate the energy output
Answer:
E_O = 96J
Explanation:
E_O = E_I*(%e/100%)
E_O = 120J*(80%/100%)
E_O = 96J
A rocket blasts off. In 10.0 seconds it is at 10,000 ft, traveling at 3600 mph. Assuming the direction is up, calculate the acceleration.
Answer:
Explanation:
Givens
t = 10 seconds
vi = 0
vf = 3600 mph
a = ?
d = 10000 feet
Formula
a = (vf - vi)/t
Solution
vf = 3600 mph * 1 hr / 3600 seconds * 5280 feet / 1 mile = 5280 ft / sec
a = (5280 - 0)/10
a = 528 ft/sec^2
An astronaut on Pluto attaches a small brass ball to a 1.00-m length of string and makes a simple pendulum. She times 10 complete swings in a time of 257 seconds. From this measurement she calculates the acceleration due to gravity on Pluto. What is her result
Answer:
The acceleration due to gravity at Pluto is 0.0597 m/s^2.
Explanation:
Length, L = 1 m
10 oscillations in 257 seconds
Time period, T = 257/10 = 25.7 s
Let the acceleration due to gravity is g.
Use the formula of time period of simple pendulum
[tex]T = 2\pi\sqrt{\frac{L}{g}}\\\\25.7 = 2 \times 31.4\sqrt{\frac{1}{g}}\\\\g = 0.0597 m/s^2[/tex]
How many meters are in 10 miles?
Answer:
Explanation:
16093.4
I need help asap please
Answer:
I dont know answer Sorry For that thank u
what will happen to the gravitational force between two bodies if the distance between them is halved keeping their masses constant ?..
1. How much heat energy ( Q ) is required to heat 2.0 kg of copper from 30.0 oC to 80.0 oC?
Answer:
38500
Explanation:
I looked it up so it may be wrong
HELP ME
Which two changes to the can opener would increase its mechanical efficiency?
A shorten the paddle so that they are closer in size to the axle that they turn
B grease the rotating wheel of the opener so that there is less breaks in between moving parts
C replaced it with a straight handle the act as levers with shorter pieces of metal
D sand the cutting surface of the metal piece so that it is perfectly smooth and sharp
Answer:
I THINK IT'S D....
HOPE SO
the weight of a body is 420 newton.calculate it's mass
Answer:
42g
Explanation:
the mass of a body is given by
m=weight/gravity
=420/10
=42
I hope this helps
when an apple falls towards the earth the earth moves up to meet the apple. Is it true? If yes, why is the earth motion not noticeable ?
Answer:
Yes, this is true.
-- While the apple is falling, the same gravitational force acts on both the apple and the Earth.
-- The mass of the apple is somewhere in the neighborhood of 1/4 kg.
-- The mass of the Earth is about 5.972 x 10²⁴ kg.
-- Since the Earth has roughly 2.389 x 10²⁶ times as much mass as the apple has, the apple has roughly 2.389 x 10²⁶ greater acceleration than the Earth has, and moves roughly 2.389 x 10²⁶ times as far down as the Earth moves up, before they smack together.
-- That's why you don't notice the Earth's motion.
-- Also, you're standing on the Earth, moving up with it, toward the apple. Maybe it would be different if you were sitting on the apple, riding it down to the ground, and you were able to notice the motion of the ground coming up to meet you at a speed that's 0.00000000000000000000000000419 of YOUR speed.
Answer From Gauth Math
The moon Phobos orbits Mars
(mass = 6.42 x 1023 kg) at
a distance
of 9.38 x 106 m. What is its period of
orbit?
[?]s
Answer:
Explanation:
We are basically needing to solve for the time in the equation d = rt, where d is the distance around Mars (aka the circumference), r is the velocity, and t is time. We need to find the circumference and the velocity. We will begin with the velocity.
Because the gravitational attraction between Phobos and Mars provides the centripetal acceleration necessary to keep Phobos in its (sort of) circular path, the equation we use for this is:
[tex]F_g=F_c[/tex] which says that Force supplied by gravity is equal to the centripetal force. Expanding that:
[tex]\frac{Gm_{Phobos}m_{Mars}}{r^2}=\frac{m_{Phobos}v^2}{r}[/tex]
When we move that around mathematically to solve for the velocity value, what we end up with is:
[tex]v=\sqrt{\frac{Gm_{Mars}}{r}[/tex] and filling in:
[tex]v=\sqrt{\frac{(6.67*10^{-11})(6.42*10^{23})}{9.38*10^6} }[/tex] and we get that
v = 2100 m/s
Now for the circumference:
C = 2πr and
C = 2(3.1415)(9.38 × 10⁶) so
C = 5.9 × 10⁷
Putting that all together in the C = vT equation:
5.9 × 10⁷ = 2100T so
T = 2.8 × 10⁴ sec or 7.8 hours
If the box of 500N is placed over the land of area of 2m²,what pressure is experted by the box on the land?
Answer:
250 Pa or N/m^2
Explanation:
Pressure(P)=F/A=500/2=250 Pa or N/m^2
A man stands still on a moving walkway that is going at a speed of 0.2 m/s to
the west. What is the velocity of the man according to a stationary observer?
A. 0.2 m/s north
B. 0.2 m/s west
C. 0.2 m/s South
D. 0.2 m/s east
When,a man stands still on a moving walkway that is going at a speed of 0.2 m/s to the west,then the velocity of the man according to a stationary observer would be 0.2 m/s west,Therefore, the correct answer would be option B.
What is Velocity?The total displacement covered by any object per unit of time is known as velocity. The velocity of an object is depend on the magnitude as well as the direction of the object.
the mathematical expression for velocity is given by
velocity = total displacement /time
The speed and velocity of the object are very different from each other because speed does not depend upon the direction of the moving object but velocity depends on the magnitude of speed as well as the direction of the moving object.
As per given in the problem a man stands still on a moving walkway that is going at a speed of 0.2 m/s to the west therefore from the perspective of a stationary observer the velocity of man would be 0.2 m/s towards West.
Hence the correct options for the problem would be option B.
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