Answer:
a) v = 18.86 m / s, b) h = 8.85 m
Explanation:
a) For this exercise we can use the conservation of energy relations.
Starting point. Like the compressed spring
Em₀ = K_e + U = ½ k x² + m g x
the zero of the datum is placed at the point of the uncompressed spring
Final point. With the spring if compress
Em_f = K = ½ m v²
how energy is conserved
Em₀ = Em_f
½ k x² + m g x = ½ m v²
v² = [tex]\frac{k}{m}[/tex] x² + 2gx
let's reduce the magnitudes to the SI system
m = 500 g = 0.500 kg
x = -45 cm = -0.45 m
the negative sign is because the distance in below zero of the reference frame
let's calculate
v² = [tex]\frac{900}{0.500}[/tex] 0.45² + 2 9.8 (- 0.45)
v = √355.68
v = 18.86 m / s
b) For this part we use the conservation of energy with the same initial point and as an end point at the point where the rock stops
Em_f = U = m g h
Em₀ = Em_f
½ k x²2 + m g x = m g h
h = ½ [tex]\frac{k}{g}[/tex] x² + x
let's calculate
h = [tex]\frac{1}{2} \ \frac{900}{9.8 } \ 0.45^2[/tex] - 0.45
h = 8.85 m
measured from the point where the spring is uncompressed
In fatal crashes, more than __________% of passenger car occupants who were totally ejected from the vehicle were killed.
Answer:
it would be 83% in a fatal crash.
A 1.5 V battery produces 41.8 mA when it is across a 30.0 Ω load. The potential difference across the battery's terminals is
Answer:
Explanation:
V = I R
V = 0.0418 * 30
V = 1.254
this battery seems dead :P
Answer:
Explanation:
Let's just assume that the battery has no internal resistance. If we get an absurd answer, we'll come back and look at that assumption.
E = I * R
I = 41.8/1000 amps = 0.0418
R = 30.0 ohms
E = 0.0418 * 30
E = 1.254 volts. This is an OK answer. The battery is a little old.
faraday's law states that the potential difference can be increased by... (choose all that apply)
1. using static electricity instead of current electricity
2. increase the number of coils, increase the strength of the magnet
3. using a bunch of small magnets
4. increasing the time used to power up an electromagnet
5. increase the speed of the magnet
Id say its the last option of the fourth option
Explanation:
Answer:
1:increase the number of coils, increase the strength of the magnet
2:increase the speed of the magnet
3: increasing the time used to power up an electromagnet
Explanation:
1). Increasing the number of turns of wire in the coil – By increasing the amount of individual conductors cutting through the magnetic field, the amount of induced emf produced will be the sum of all the individual loops of the coil, so if there are 20 turns in the coil there will be 20 times more induced emf than in one piece of wire.
2). Increasing the speed of the relative motion between the coil and the magnet – If the same coil of wire passed through the same magnetic field but its speed or velocity is increased, the wire will cut the lines of flux at a faster rate so more induced emf would be produced.
3). Increasing the strength of the magnetic field – If the same coil of wire is moved at the same speed through a stronger magnetic field, there will be more emf produced because there are more lines of force to cut.
a car whose tires have radii of 50cm travels at 20km/h. what is the angular velocity of the tire
Answer:
0.225 s^-1
Explanation:
Please mark as brainliest
The angular velocity of the tire is 11.12 rad/s.
Angular velocity: This is the change in angular direction per time. The S.I unit is rad/s.
⇒ Formula:
v = rω.................... Equation 1⇒ Where:
v = linear velocity of the carr = radius of the carω = angular velocity of the car⇒ Make ω the subject of the equation
ω = v/r.............. Equation 2From the question,
⇒ Given:
v = 20 km/h = 20(1000)/(3600) m/s = 5.56 m/sr = 50 cm = 50/100 = 0.5 m⇒ Substitute these values into equation 2
ω = 5.56/0.5ω = 11.12 rad/sHence, The angular velocity of the tire is 11.12 rad/s
Learn more about angular velocity here: https://brainly.com/question/20432894
A Cambra pouce car traveling at 28 m/s slow
at a rate of at 3.6 m/s every second find.
a) The time taken for the police car to come to Stop?
Answer:
t = 7.8 seconds
Explanation:
Given that,
The initial speed of the car, u = 28 m/s
Acceleration of the car, a = 3.6 m/s²
We need to find the time taken for the police car to come to Stop. When it stops, its final speed is equal to 0. So, using the equation of kinematics to find it i.e.
[tex]v=u+at\\\\0=28+3.6t\\\\t=\dfrac{28}{3.6}\\\\t=7.8\ s[/tex]
So, the required time is 7.8 seconds.
Which bond(s) shown are double bonds?
Answer:
I'm pretty sure its the 2nd one.
Arrange the following substances from the lightest to the heaviest:
Cl2, CH4; H20; NH3, N2
A. H2O<NH,< N2 CH4Cl2
B. CH< NH< H-0< < Cl2
C. Ny< Cl< H2O< CH«<NH3
D. NH;< CH«< Cl< H2O< N2
molecular weights are written in the picture.
CH4<NH3<H2O<Cl2
Need a little help here, ASAP please. The subject is simple science, not physics.
I need help with science please, ill give brianlist’s :
Question 1 :The size of a plant cell may change depending upon the amount of water it receives.
True
False
________________________________
Question 2: Chloroplasts are a category of organelles found in the cells of green plants.
True
False
_______________________________
Question 3: Photosynthesis in plants produces water and carbon dioxide.
True
False
Answer:
true , true, and I'm not sure about the last one!
Explanation:
Which of these is NOT a form of energy?
A. mechanical
B. chemical
C. theoretical
D. thermal
Answer:
I think it's theoretical.
Energy is radiated or transmitted in the form of rays or waves or particles.
B. radiation
C. convection
D. conduction
Answer:
B radiation
Explanation:
every type of transmitted waves are radioactive in a way.
A train car, which has a mass of 2000 kg, is rolling along with a velocity of 20 m/s East. It
strikes a stationary car, which also has a mass of 2000 kg, and they stick together after the
collision. What is their final velocity? (include appropriate units in your answer) * 15
10m/s East
Explanation:
p=mv
m1v1 = m2v
p = m1v1
2000kg*(20m/s) = 40000kg*m/s
Add the two masses together for m2
p = m2v2
40000kg*m/s = 4000kg * v2
v2 = 10m/s
Help please thank you
anser: 27s PoP
Explanation:
1 is the force, so the equal antiforce will be 1. weight of car divided by force from engine
34 pop / s = 129
27pOp
Find the velocity of a dolphin that swims 55 m in 5.0 s.
Answer: 11 m/s
Explanation: velocity = distance /time = 55 m /5.0 s
Answer:40km/h
Explanation:
PLEASE HELP
The spine is part of which system?
A. Circulatory System
B. Central Nervous System
C. Endocrine System
Answer:
Explanation:
B. Central Nervous System
What must exist for the engineering process to begin?
a. a problem
ь.a solution
c. research
d. scientific tools
Answer:
d
Explanation:
rzp-yyib-oiv
plèase jóin ón góógle mèèt
Answer:
a. a problem
Explanation:
The engineering process begins by defining a problem and completing background research on the problem.
A 55.0 kg bungee jumper steps off a bridge with a light bungee cord tied to her and to the bridge. The unstretched length of the cord is 15.0 m. She reaches the bottom of her motion 40.0 m below the bridge before bouncing back. Her motion can be separated into an 15.0 m free-fall and a 25.0 m section of simple harmonic oscillation. Use the principle of conservation of energy to find the spring constant of the bungee cord.
Answer:
[tex]69.06\ \text{N/m}[/tex]
Explanation:
m = Mass of bungee jumper = 55 kg
g = Acceleration due to gravity = [tex]9.81\ \text{m/s}^2[/tex]
h = Height at the bottom = 40 m
k = Spring constant
x = Displacement of bungee cord = 25 m
Applying the principle of conservation of energy to the system we have
[tex]mgh=\dfrac{1}{2}kx^2\\\Rightarrow k=\dfrac{2mgh}{x^2}\\\Rightarrow k=\dfrac{2\times 55\times 9.81\times 40}{25^2}\\\Rightarrow k=69.06\ \text{N/m}[/tex]
The spring constant of the bungee cord is [tex]69.06\ \text{N/m}[/tex].
g A 4 lb weight stretches a spring 2 ft in equilibrium. It is attached to a damping mechanism with constant c. (a) Find the value of c for which the motion is critically damped. (b) If the motion is critically damped, find the displacement y(t) when the spring is initially displaced 6 inches above equilibrium and given a downward velocity of 3 ft/sec.
Solution :
Given :
Weight = 4 lb
Stretched of a spring in equilibrium,Δ = 2 ft
a). We know that
F = kΔ
4 = k x 2
k = 2 lb/ft
∴ Stiffness of the spring is, k = 2 lb/ft
Motion is critically damped.
[tex]$\epsilon = 1$[/tex]
[tex]$\epsilon=\frac{C}{C_c} = 1$[/tex]
[tex]$C=C_c[/tex]
[tex]$C=C_c=\sqrt{4k_m}[/tex]
[tex]$C=\sqrt{4 \times 2 \times \left(\frac{4}{32.174}\right)}[/tex]
C = 0.99729 lb.s/ft.
b). Displacement
[tex]$y(t)=y_0 \sin (\omega t)$[/tex]
[tex]$\dot{y}(t)= y_0 \omega \cos (\omega t)$[/tex]
[tex]$[\dot{y}(t)]_{mon}= y_0 \omega $[/tex]
Initial displacement = 6 inches
[tex]$y_0 = 0.5 \ ft , \ \ \ \dot y (t) = 3 \ ft/sec$[/tex]
[tex]$\Rightarrow 3=0.5 \times \omega$[/tex]
[tex]$\Rightarrow \omega = 6$[/tex]
Therefore, displacement :
[tex]$y(t)=y_0 \sin (\omega t)$[/tex]
[tex]$y(t)=0.5 \sin (6 t)$[/tex]
After landing on an unexplored Klingon planet, Spock tests for the direction of the magnetic field by firing a beam of electrons in various directions and by recording the following observations:1. Electrons moving upward feel a magnetic force in the northwest direction.2. Electrons moving horizontally toward the north are pushed downward.3. Electrons moving horizontally toward the southeast are pushed upward.Mr. Spock therefore concludes that the magnetic field at this landing site is in which direction?A) toward the eastB) toward the northeastC) toward the southwestD) toward the southeastE) toward the west
Answer:
the correct one is C,
Explanation:
The magnetic force is given by the expression
F = q v x B
where the bold letters indicate vectors, we can find the modulus of this expression
F = q v B sin θ
The direction of the to the force with the rule of the right hand. The thumb applies in the direction of the speed, the fingers extended in the direction of the magnetic field and if the charge is positive the palm is in the direction of the force, if the charge is megative the force is in the opposite direction to the palm of hand.
Let's analyze the different situations presented; As the particles emitted are electrons, their charge is negative.
Situation 1. The thumb points upwards, the force is towards the NW as the charge is negative, the palm points towards the SE therefore the finger points towards the SOUTHWEST which must be the direction of the magnetic field
Situation 2. the electrons go horizontally to the north the thumb points in this direction, the force is downwards, therefore the palm points upwards, the extended fingers point to the WEST
Situation 3. the thumb points to the SE towards where the electrons move, the force is upwards the palm points to the SW, therefore the fingers extended points SOUTHWEST
As a result of situations 1 and 3 the magnetic field must point in the SOUTHWEST direction.
Situation 2 gives a different result because the component of the field that is directed to the south does not create exerts and therefore cannot be detected.
When checking the answers, the correct one is C
. Four railroad cars, each of mass 2.50 104 kg, are coupled together and coasting along horizontal tracks at a speed of vi toward the south. A very strong but foolish movie actor, riding on the second car, uncouples the front car and gives it a big push, increasing its speed to 4.00 m/s southward. The remaining three cars continue moving toward the south, now at 2.00 m/s. (a) Find the initial speed of the cars. (b) How much work did the actor do
Answer:
a) v₀ = 2.5 m / s, heading south.
b) W = 1,219 10⁵ J
Explanation:
a) For this exercise we can use the conservation of the moment, we create a system formed by all the 4 cars, in this case when the last one separates the forces are intense and the moment is conserved
initial instant. Before separation
p₀ = M v₀
final instant. When uncoupling the last car
p_f = 3m v₁ + m v₂
where they indicate that the speed of the wagons is v₁ = 2.00 m / s and the speed of the last wagon is v₂ = 4.00 m / s
the total mass is M = 4m
how the moment is preserved
p₀ = p_f
4m v₀ = 3m v₁ + mv₂
v₀ = ¾ v₁ + v₂ / 4
let's calculate
v₀ = ¾ 2 + ¼ 4
v₀ = 2.5 m / s
heading south.
b) work is equal to the change in kinetic energy
W = ΔK = K_f -K_o
W = ½ m v_f² - ½ m v₀²
W = ½ m (v_f² -v₀²)
W = ½ 2.50 10⁴ (4² - 2.5²2)
W = 1,219 10⁵ J
As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arranged side by side so that they are parallel to each other. When you push the platform, you compress the springs. You do an amount of work of 76.0 J when you compress the springs a distance of 0.170 m from their uncompressed length.
(a) What magnitude of force must you apply to hold the platform in this position?
(b) How much additional work must you do to move the platform 0.200 m farther, and what maximum force must you apply?
Answer:
[tex]894.12\ \text{N}[/tex]
[tex]284.013\ \text{J}[/tex]
Explanation:
U = Energy = 76 J
x = Displacement of spring = 0.17 m
k = Spring constant
Energy is given by
[tex]U=\dfrac{1}{2}kx^2\\\Rightarrow k=\dfrac{2U}{x^2}\\\Rightarrow k=\dfrac{2\times 76}{0.17^2}\\\Rightarrow k=5259.51\ \text{Nm}[/tex]
Force is given by
[tex]F=kx\\\Rightarrow F=5259.51\times 0.17\\\Rightarrow F=894.12\ \text{N}[/tex]
The magnitude of force must you apply to hold the platform is [tex]894.12\ \text{N}[/tex].
Now [tex]x=0.17+0.2=0.37\ \text{m}[/tex]
[tex]U=\dfrac{1}{2}kx^2\\\Rightarrow U=\dfrac{1}{2}\times 5259.51\times 0.37^2\\\Rightarrow U=360.013\ \text{J}[/tex]
Additional energy
[tex]360.013-76=284.013\ \text{J}[/tex]
how much force is needed to accelerate a 2500kg car at a rate of 4m/s2
Answer:
10,000 N
Explanation:
Using Newton's Second Law of Motion, Force = Mass*Acceleration.
Plugin 2500 kg for the mass and 4 m/s^2 for the acceleration.
Force = 2500 kg*4 m/s^2 = 10000 Newtons
(SI unit of force is Newtons)
what is the formula that describes the magnitude of impulse on an object?
Answer:
Option C.
Impulse = mass × change in velocity
Explanation:
Impulse is defined by the following the following formula:
Impulse = force (F) × time (t)
Impulse = Ft
From Newton's second law of motion,
Force = change in momentum /time
Cross multiply
Force × time = change in momentum
Recall:
Impulse = Force × time
Thus,
Impulse = change in momentum
Recall:
Momentum = mass x velocity
Momentum = mv
Chang in momentum = mass × change in velocity
Change in momentum = mΔv
Thus,
Impulse = change in momentum
Impulse = mass × change in velocity
A student adds 5 grams of vinegar to 7 grams of baking soda in a sealed bag. Then she watches the bag inflate as a chemical
reaction occurs. Which of these amounts is a CORRECT prediction of the mass of the materials in the container after the reaction is
complete?
Answer:
The mass will stay the same if the bag stays sealed.
Explanation:
When will heat STOP flowing
between two objects?
A. When one object is significantly
warmer than the other
B. When one object is significantly cooler
than the other
C. Never
D. When both objects reach the same
temperature
Answer: D. When both objects reach the same temperature.
Explanation: When will heat flow between the objects stop? Heat will always flow from the warmer object to the colder object. The heat transfer will stop when the two objects are at the same temperature and reach thermal equilibrium.
Answer: Heat will always flow from the warmer object to the colder object. The heat transfer will stop when the two objects are at the same temperature and reach thermal equilibrium.
so the answer to your question is c
Explanation:
What is relative density?
11. There are 2 main reasons geologists think the continents were once connected. One
reason is that some coastlines share similar fossils. What is the other reason? II
Answer:
they all kinda fit together like a puzzle also because they can tell now that the continates are moving so, they can asume that they have always been moving
Please help
The period of an oscillation is measured to be 0.0833 seconds. What is
the frequency of this oscillation? *
1.0833 Hz
0.287 Hz
9.8 Hz
12 Hz
0.007 Hz
Answer:
your
answer is
12.004
given that two vectors A=i,2j-2k and B=6i+3j+2k find A +B
Answer:
7i, 5j, 0k
Explanation:
Add up the two vectors.
Add
i+i 1+6 = 7i
j+j 2+3 = 5j
k+k -2+2 = 0k
therefore A+B = (7i, 5j, 0k)
Sections or chunks of material where atoms are lined up with each other are called...
Answer:
Magnetic domains
Explanation:
Because when the electrons spin around the necleus of an atom, it causes the atom to become a tiny magnet