Answer:
-4000 N
Explanation:
1. First let's look at what we know.
Mass: 1000 kg
Initial velocity: 20 m/s
Final velocity: 0 m/s
Displacement: 50 m
2. Let's try and apply a Kinematics equation here.
Looking at what information we have, I would say that this is the best equation:
v[tex]f^{2}[/tex]=v[tex]o^{2}[/tex] + 2aΔx
3. Plug in the numbers.
0 = 400 + 2(a)(50)
0 = 400 + 100a
-400 = 100a
a = -4 m/s^2
4. Use ∑F=ma
∑F = (1000)(-4)
∑F = -4000 N
Which of the answers shows three examples of a physical change
A wooden object (conically shaped) has a diameter of 8cm and height of 14cm. It floats in oil with 6cm of its height above oil level. Determine (a)The density of the object (b) If the volume of oil is twice that of the object, what fraction of oil is displaced after immersing the object?
Answer:
(a) The density of the object is 316/343 × the density of the oil
(b) The fraction of oil displaced after immersing the object is 0.461 of the oil volume
Explanation:
(a) The volume, V of a cone of height, h and base diameter, D = 2×r is given by the following equation;
[tex]V = \dfrac{\pi r^{2} h}{3}[/tex]
The volume of the object is therefore;
[tex]\dfrac{\pi \times 4^{2} \times 14}{3} = 74\tfrac{2}{3}\pi \, cm^3[/tex]
Where 6 cm is above the oil level we have;
[tex]\dfrac{\pi \times \left (6 \times \dfrac{4}{14} \right )^{2} \times 6}{3} = 5\tfrac{43}{49}\pi \, cm^3[/tex] above the oil level
Therefore, volume of the oil displaced = [tex]68\tfrac{116}{147}\pi[/tex] cm³ = 216.11 cm³
The density of the object is thus;
[tex]\dfrac{68\tfrac{116}{147}\pi}{ 74\tfrac{2}{3}\pi} \times Density \ of \ the \ oil = \dfrac{316}{343} \right ) \times Density \ of \ the \ oil[/tex]
The density of the object = 316/343 × the density of the oil.
(b) The volume of the oil = 2 × Volume of the object = [tex]2 \times 74\tfrac{2}{3}\pi \, cm^3 = 149\tfrac{1}{3}\pi \, cm^3[/tex]
The fraction of the volume displaced, x, after immersing the object is given as follows;
[tex]x = \dfrac{68\tfrac{116}{147}\pi}{ 149\tfrac{1}{3}\pi} = \dfrac{158}{343} = 0.461[/tex]
The fraction of oil displaced after immersing the object = 0.461 of the volume of the oil
What happens to sound waves after they are received by our ears?
Answer:
Our ears perceive then sound then it is transmitted to our brain where it is processed into something we can respond to. This all happens in less than a second and we are unaware that we are doing it.
Explanation:
The sound wave bounces off of the ear drum into the inner ear.
Answer:
Sound waves travel from the outer ear and in through the auditory canal, causing the eardrum to vibrate. This in turn causes three small bones in the middle ear to move. The vibrations move through the fluid in the cochlea in the inner ear, stimulating thousands of tiny hair cells.
:What will be the value of the refractive index of the medium? Critical angle of that medium is 30 degree
a) 2
b) 1.5
c) 1.8
d) 1
Answer:
Let the second medium be air (n₁=1)
The refractive index n₂ of the medium where first medium is air is found (a)
(a) n₂ = 2
Explanation:
Critical angle can be defined as the angle of incidence that provides the angle of refraction of 90°.
Refractive index of a medium can be defined as a number that describes that how fast a light will travel through that medium.
Critical angle and Refractive index are related by:
[tex]\theta_{critical}= sin^{-1}(\frac{n_1}{n_2})[/tex]
[tex]sin \theta_{critical}=\frac{n_1}{n_2}[/tex]
To find refractive index of medium with respect to air, substitute n₁=1 (Refractive index of air is 1)
Also θ(critical)=30°
Find n₂ :
[tex]sin30= \frac{1}{n_2}\\0.5=\frac{1}{n_2}\\n_2=\frac{1}{0.5}\\n_2=2[/tex]
Which of these correctly describes what would happen to a system if 100 J of heat energy is added to it?
1. The potential energy of the system will increase and this will increase the attraction between its particles.
2. The strength of the bonds in system will increase and this will decrease the speed of its particles.
3. The kinetic energy of the system will increase and this will increase the speed of its particles.
4. The kinetic energy of the system will decrease and this will decrease the speed of its particles.
The correct statement to describe that when a 100 J of heat energy is added to the system, then the kinetic energy of the system will increase and the speed of the particles will also increase. Hence, option 3 is correct.
What is Kinetic energy?The force that an object has because it is moving is known as kinetic energy in physics. It is defined as the quantity of effort required to accelerate anybody of a specific mass from rest to its specified velocity. The body keeps its kinetic energy after acquiring it during acceleration, barring changes in speed.
When slowing from its current pace to a condition of rest, the body expends the very same amount of energy. Any term in the Lagrangian of a system that has a derivative in regard to time is formally referred to as kinetic energy.
When the energy is added to the system the gap between the particles will increase due to which the velocity of the molecules will increase and with increase in the velocity the kinetic energy will also increase automatically.
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Hannah knows she has some natural skill at field hockey, but she never practices in the off season. This is an example of
Answer:
wasting talent
Explanation:
What does the law of conservation of energy state about both sides of the chemical reaction
Answer: D
Explanation: Energy is neither created nor destroyed so the amount of reactants and products must be equal
1. What is the inductance of a series RL circuit in which R= 1.0 K ohm if the current increases to one-third of
its final value in 30 micro s?
Answer: the answer is C its in the book
Explanation:
Ax = 44.4 m and Ay = 25.1 m Find the direction of the vector.
Answer: 29.5 degree
Explanation: Given that
Ax = 44.4 m and Ay = 25.1 m
The direction of the vector will be
Tan Ø = Ay/Ax
Substitute Ay and Ax into the formula
Tan Ø = 25.1/44.4
Tan Ø = 0.5653
Ø = tan^-1(0.5653153)
Ø = 29.48 degree
Ø = 29.5 degree approximately.
Therefore, the direction of the vector is 29.4 degrees approximately.
What are two ways to increase impulse?
Answer:
increase the time the force acts or you could increase the number of temptations.
hope this helped!
Which one of the following is not equivalent to 2.50 miles?
(1.00 mi = 1.61 km = 5280 ft, 1.00 yd = 3.00 ft = 12.0 in.)
(A) 1.32 x 104 ft
(B) 1.58 x 105 in
(C) 4.02 x 103 km
(D) 4.40 x 103 yd
(E) 4.02 x 105 cm
Answer:
Choice C is not equivalent to 2.50 miles.
Explanation:
The given data is now converted into feet, inches, kilometers, yards and centimeters:
mi - ft
[tex]x = (2.50\,mi)\cdot \left(5280\,\frac{ft}{mi} \right)[/tex]
[tex]x = 13200\,ft[/tex]
[tex]x = 1.320\times 10^{4}\,ft[/tex] (Choice A)
mi - in
[tex]x = (2.50\,mi)\cdot \left(5280\,\frac{ft}{mi} \right)\cdot \left(12\,\frac{in}{ft} \right)[/tex]
[tex]x = 158400\,in[/tex]
[tex]x = 1.584\times 10^{5}[/tex] (Choice B)
mi - km
[tex]x = (2.50\,mi)\cdot \left(1.61\,\frac{km}{mi} \right)[/tex]
[tex]x = 4.025\,km[/tex] (Different from Choice C)
mi - yd
[tex]x = (2.50\,mi)\cdot \left(5280\,\frac{ft}{mi}\right) \cdot \left(\frac{1}{3}\,\frac{yd}{ft} \right)[/tex]
[tex]x = 4400\,yd[/tex]
[tex]x = 4.40\times 10^{3}\,yd[/tex] (Choice D)
mi - cm
[tex]x = (2.50\,mi)\cdot \left(1.61\,\frac{km}{mi} \right)\cdot \left(100000\,\frac{cm}{km}\right)[/tex]
[tex]x = 402500\,cm[/tex]
[tex]x = 4.025\times 10^{5}\,cm[/tex] (Choice E)
Choice C is not equivalent to 2.50 miles.
A piston has an area of 4 m2 and needs 20 N of force to push it down. What is the pressure?P=F/A *
A) 5 Pa
B) 0.2 Pa
C) 80 Pa
D) 20 Pa
brainliest for the best answer!
for besties with scienceeee!! asap plzz
The throwback PFD is which type?
Answer:a
Explanation:
The throwback PFD is a Type III PFD. This type of PFD is designed for calm, inland water, or where there is a good chance of quick rescue. THe correct option is C.
Type III PFDs will not turn unconscious wearers to a face-up position, so the wearer may have to tilt their head back to avoid turning face down.
Type III PFDs have the same minimum buoyancy as Type II PFD. Float coats, fishing vests, and vests designed for various water sports are examples of Type III PFDs. Some Type III PFDs are designed to be inflated upon entering the water.
Offshore life jackets of Type I are suited for all areas, notably open, choppy, or isolated regions where rescue may be delayed and offer the highest buoyancy. Near-shore vests of Type II PFDs are designed for calm inland water or situations where there is a good probability of prompt rescue. Throwable PFDs of Type IV are suitable for usage in open water as well as calm, heavily used inland waters where assistance is always available. Special-purpose PFDs known as Type Vs are made for activities like kayaking and whitewater rafting.
The throwback PFD is not a Type I PFD because it does not provide the most buoyancy and is not designed for all waters. It is not a Type II PFD because it is not intended for calm, inland water or where there is a good chance of quick rescue. It is not a Type IV PFD because it is not intended for calm, inland water with heavy boat traffic, where help is always present. It is not a Type V PFD because it is not designed for specific activities such as kayaking or whitewater rafting.
Therefore, the correct option is C. type III.
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A vector points 12.0 units along the x-axis, and 9.00 units along the y-axis. Find the direction of the vector
The resultant points somewhere between the positive x and y axes.
The angle it makes with the x-axis has a tangent of (9/12) = 0.75 .
That angle is 36.9°, rounded to the nearest tenth of a degree.
So the resultant vector points up and to the right, 36.9° above the x-axis.
Which of the following planets helped astronomers locate another planet?
Group of answer choices
Mercury
Uranus
Saturn
Pluto
Answer: Pluto,Mercury
Explanation:
Which diagram is the best model for a solid ?
A model of an atom is useful when it
Select one:
O a. is shown only as the planetary model
b. shows exactly what an atom looks like
c. helps to visualize processes that cannot be seen with our eyes
d. magnifies what the eye can't see
If you wanted to learn more about ancient scientific knowledge, whose life
would you research?
Answer:
I would like to research Nikola Tesla's life
Help ASAP please (: The waves with the MOST energy have
amplitudes.
frequencies and
A) low; large
B) low; small
C) high; large
D) high; small
Answer: C
high; large
Explanation:
The wave energy is related to its amplitude and frequency.
The wave energy is proportional to the amplitude of the wave. So, wave with the most energy will have high amplitude.
Also, frequency is related to wave energy. The larger the frequency, the more the energy of the wave.
Therefore, The waves with the MOST energy have high amplitudes and large
frequencies.
Does anyone know how to do this question???
Force = 7kN
Pressure = 1mPa
Area = ?
Answer:
7000 m^2
Explanation:
Pressure=Force/Area
1=7000/Area
1(Area)=7000
Area=7000 m^2
The diagram shows a motion map
Which best describes the motion of the object between 1
and 4 seconds
toata
• The object has decreasing acceleration and increasing
velocity
The object has positive acceleration and eventually
stops
The object has decreasing acceleration and decreasing
velocity
The object has negative acceleration and eventually
stops
Answer:
the object has decreasing acceleration and increasing velocity
I WILL CHOOSE YOU AS THE BRAINIEST PLEASE ANSWER MY QUESTION
Identify that all objects exert a force of gravity on all other objects in the universe
Answer:
It's like the Earth pulling on you and keeping you on the ground. That pull is gravity at work. Every object in the universe that has mass exerts a gravitational pull, or force, on every other mass. The size of the pull depends on the masses of the objects.
Explanation:
10. Almost three-quarters of household energy use is due to the following:
• home furnaces and air conditioners
• water heaters
• washers and dryers
• lighting
For each of these uses of energy, give two reasonable ways to reduce household
energy consumption
Answer: Energy consumption and sustainability is important so that it remain available for future generation.
Explanation:
1. The home furnaces are likely to require fuel like coal, which will directly emit carbon dioxide and carbon monoxide gases. These should be replaced with the electrical furnaces. The old or more power consuming air conditioners should be replaced with new ones.
2. The water heaters should be tankless so their capacity to heat more water could be possible. The water heaters should be electricity saving.
3. Washer and dryers should be water savy and electricity savy. A front-loading washing machine is useful energy saver.
4. The LED lights are more electricity saving than conventional bulbs. Halogen lights are also electricity saving.
A truck accelerated from a velocity of 20 m/s to velocity of 5 m/s in a period of 5 seconds. Determine the acceleration of the truck with the proper units.
A. 2 meters/ second
B. -3 meters/ second
C. 3 meters/ second squared
D. -3 meters/ second squared
Two bumper cars collide and then move away from each other. The forces exerted are:
A. Equal and opposite
B. Opposite
C. Equal
Answer:
the answer is b
Explanation:
if it was equal they would move away from each other
PLEASE HELP THIS IS MY LAST QUESTION!!! HELP ASAP!!
Which of these does NOT have gravity?
A. heat
B. an apple
C. a small moon
D. Earth's atmosphere
Answer: its A
Explanation: it cant be earths atmosphere because is it was we would be flouting
Answer:
a
Explanation:
ILL MARK YOU THR BRAINLIEST SOMEONE PLS HELP ITS URGENT.
The acceleration of a skydiver of mass 80 kg changes from 9.8 m/s ^ 2 to 5.8 m/s ^ 2 as he falls through the air. What is the air resistance experienced by him?
Answer:
320N
Explanation:
Net force =w- AR
AR=w -force
AR=mg- ma
AR=80*9.8- 80*5.8
AR=784- 464
AR=320N
A girl is out jogging at 2.00 m/s and accelerates at 1.50 m/s^2 until she reaches a velocity of 5.00 m/s. How far does she get?
Answer:
7.00 m
Explanation:
Given:
v₀ = 2.00 m/s
v = 5.00 m/s
a = 1.50 m/s²
Find: Δx
v² = v₀² + 2aΔx
(5.00 m/s)² = (2.00 m/s)² + 2(1.50 m/s²)Δx
Δx = 7.00 m
Question 2 (2 points)
Practice tests are available online.
True
False
K12
How does a force do negative work on an object
Answer:
Explanation:
How does a force do negative work on an object ; This is when the direction of motion is opposite to the direction of the force
To solve this we must be knowing each and every concept related to work. Therefore, a force do negative work on an object, when the direction of motion is opposite to the direction of the force.
What is work?A task requiring mentally or physically effort in order to accomplish a goal or outcome is referred to as labor in general. When we lift heavy objects off the ground or push or pull large objects, we are performing labor. When the direction of motion is opposite to the direction of the force, work is negative.
Another word we frequently use is energy. Energy and amount of work performed are typically associated, because a person who's really feeling particularly excited is capable of accomplishing a lot of work.
Therefore, a force do negative work on an object, when the direction of motion is opposite to the direction of the force.
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