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]
The hair dryer has a plastic case so there is no need for an earth wire connection in the plug ,explain why the hair dryer is still safe to use.
Answer:
plastics are unable to conduct electricity and heat due to there being no free flowing electrons, meaning they are safe to use.
Explanation:
A car is traveling at 36km/h when it accelerates and after 2 seconds the car reaches a speed of 54km/h. Calculate the speed of the car in 2s?
Mass of the sun is 2x10³⁰ kg and that of the earth is 6/10²⁴ kg and the distance between them is 1.5 x 10¹¹m. What is the gravitational force produced between them?
Answer:
The gravitational force is 3.56 × 10^22 N
Explanation:
[tex]{ \bf{force = \frac{GM_{s} m _{e}}{ {r}^{2} } }}[/tex]
[tex]{ \sf{force = \frac{6.67 \times {10}^{ - 11} \times (2 \times {10}^{30} ) \times (6\times {10}^{24}) }{(1.5 \times {10}^{11}) {}^{2} } }} \\ \\ { \sf{force = 3.56 \times {10}^{22} \: newtons}}[/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.
the mass of earth is 6*10^24 and of mars is 6*10^23 and gravitational force is 6.67*10^16 ,find the distance between their centres.
Answer:
6× 10¹⁰ metres
Explanation:
F=(G×M1×M2)/r²
(6.67×10¹⁶)=((6.67×10^-11)(6×10²⁴)(6×10²³))/r²
r²=3.6×10²¹
Therefore r=6×10¹⁰ metres
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 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]
a car moves at a speed of 40km/h. it is stopped by applying brake which produce a uniform acceleration of-0.5m/s^2. how much distance will it move before coming to stop ? plz its urgent
Answer:
Explanation:
I answered this in question #24313516
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
How much power does it take to lift a box with a weight of 50N to put it on a shelf that is 10m high in
10 sec?
We know
[tex]\boxed{\sf Power=\dfrac{Work\:done}{Time}}[/tex]
[tex]\\ \sf\longmapsto Power=\dfrac{Force\times displacement}{Time}[/tex]
[tex]\\ \sf\longmapsto Power=\dfrac{50\times 10}{10}[/tex]
[tex]\\ \sf\longmapsto Power=\dfrac{500}{10}[/tex]
[tex]\\ \sf\longmapsto Power=50W[/tex]
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.
Kgms-1-= Ns ...solution
Answer:
units of impact or impulse or momnetum are same
These are
Kg m s-1 or N s
-8. A vessel is filled with a 20cm of water. When an irregular body of mass 800gm is immersed the volume of water is increased to 60cm3. What is the density of irregular shaped body?
Answer:
13.33 g/cm3
Explanation:
density = mass/volume
mass of irregular body = 800 grams
new volume = 60 cube cm
= density = 800/60 = 13.333 g/cm3
In which instrument of the following the water works as a bulb
Answer:
hydrometer
Explanation:
A hydrometer is an instrument used to determine specific gravity. It operates based on the Archimedes principle that a solid body displaces its own weight within a liquid in which it floats. Hydrometers can be divided into two general classes: liquids heavier than water and liquids lighter than water.
Which class of lever has all advantages of lever
Answer:
Helo ....
so this answer would be First class levers
becoz...
First-class levers have a considerable practical advantage over the other types of levers. They convert a downward moving force into a lifting force
is it possible to mark it brainliest <3
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
Learn more about Doppler's Effect here:
https://brainly.com/question/1330077?referrer=searchResults
7. A thin wire was wound 30 times closely over a boiling tube. The total length of the windings as measured was found to be 6.3mm. Determine the diameter of the wire .
Answer:
Diameter of wire = 0.00021 meters
Explanation:
Given the following data;
Number of windings = 30
Length of windings = 6.3 mm to meters = 0.0063 meters
To find the diameter of the wire, we would use this mathematical expression;
Length of windings = number of windings * diameter of wire
Substituting the values into the expression, we have;
0.0063 = 30 * diameter of wire
Diameter of wire = 0.0063/30
Diameter of wire = 0.00021 meters
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.
3. A microwave oven draws 12 A of current on a 110 V household circuit. What is its power
rating?
Answer:
W = 1320Watts
Explanation:
W = I*V
W = 12A*110V
W = 1320Watts
Define measurement and write its importance.
Answer:
Measurement is the way humans define certain amounts of matter, and is expressed in various types of units respective to the type of matter or object being defined.
Explanation:
Measurement is extremely important because it helps one another understand how much of something is needed to accomplish something. If no method existed to define the specific amount needed, we would simply mess delicate operations up and machines, even simple recipes, would fail.
How many atoms are in the compound NaNO3?
Explanation:
3 atoms are in the compound
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.
28 Why is soft iron used for the core of an electromagnet?
А Soft iron easily becomes a permanent magnet.
B Soft iron is a good electrical conductor.
с Soft iron is a poor thermal conductor.
D Soft iron loses its magnetism when the current in the coil is switched off.
Answer:
An electromagnet is a form of magnet that is made by the passage of electric current through a coil of wire. The core of an electromagnet increases the strength of the produced magnetic field
Soft iron is used as the core of an electromagnet because soft iron is a magnetic material and therefore it is permeable to and becomes magnetized by the magnetic field coming from the flowing current, thereby allowing more flux to pass through the core of the electromagnet, producing a magnetic field strength that is several times that of an air core electromagnet as the relative permeability (to magnetic flux, compared to vacuum) of soft iron is about 64 × 10³
However, once the current is switched, the soft iron does not remain its magnetic, and therefore, the electromagnet becomes demagnetized, thereby being able to maintain its electromagnetic characteristics (being made magnetic by the flow of electric current)
Explanation:
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
a load of 800 newton is lifted by an effort of 200 Newton. if the load is placed at a distance of 10 cm from the fulcrum. what will be the effort distance ?
Answer:
40 cm
Explanation:
We are given that
Load=800 N
Effort=200 N
Load distance=10 cm
We have to find the effort distance.
We know that
[tex]load\times load\;distance=Effort\times effort\;distance[/tex]
Using the formula
[tex]800\times 10=200\times effort\;distance[/tex]
Effort distance=[tex]\frac{800\times 10}{200}[/tex]
Effort distance=[tex]\frac{8000}{200}[/tex]
Effort distance=40 cm
Hence, the effort distance will be 40 cm.
Can someone help me please this test is very important
Answer:
Friction is caused in roller coasters by the rubbing of the car wheels on the track and by the rubbing of air (and sometimes water!) against the cars.
Explanation:
If the force on a spring is 2 N and it stretched 0.5 m, what is the spring constant?
O A. 2 N/m
OB. 0.2 N/m
OC. 0.4 N/m
OD. 4 N/m
answer is
0.4n/mthe 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
This happens because the.....particles are most likely to escape from the liquid, causing the temperature of the liquid to.....
Answer:Boiling
Explanation: If a liquid is heated the particles are given more energy and move faster and faster expanding the liquid. The most energetic particles at the surface escape from the surface of the liquid as a vapour as it gets warmer.
