1. How are hot and cold packs constructed so that the reaction takes place only when needed?
2. Hypothesize two ways that you could change the amount of heat given off or absorbed in these packs.
Answer:
1.They are constructed of a large pouch containing a dry chemical plus an inner pouch of water. The hot/cold pack is activated by breaking the seal on the pouch of water and shaking the pack vigorously. This action mixes the water
A SOUND WAVE WITH ITS CHARACTERISTIC PATTERN OF COMPRESSIONS AND
RAREFACTIONS IS SHOWN BELOW. A CENTIMETER RULER IS INCLUDED BELOW THE
PATTERN THE WAVELENGTH OF THIS SOUND WAVE IS HOW MANY cm?
A 2 cm
B 3 cm
C 35 cm
D. 85 cm
וייייייייייייייייי
U
0
1
2
3
4
5
6
7
8
9
10
Answer:
The wavelength is 1.7cm
Explanation:
Given
See attachment for wave pattern
Required
What is the wavelength
To do this, we simply calculate the distance between successive waves (see attachment 2 for point A and B)
Using the ruler, points A and B are at:
[tex]A = 0.6cm[/tex]
[tex]B = 2.3cm[/tex]
So, the wavelength is:
[tex]\lambda = B - A[/tex]
[tex]\lambda = 2.3cm - 0.6cm[/tex]
[tex]\lambda = 1.7cm[/tex]
If approximated, the wavelength is:
[tex]\lambda \approx 2cm[/tex]
Use this free body diagram to help you find the magnitude of the force needed to keep this block in static equilibrium.
А.15.3 newtons
В.36.3 newtons
C. .63.5 newtons
D. 95.5 newtons
Split F₁ into its horizontal and vertical components:
F₁ = F₁ cos(θ) i + F₁ sin(θ) j
(boldface = vector; regular font = magnitude)
By Newton's second law, if the object is in equilibrium, then
• the net horizontal force on the block is
∑ F = F₁ cos(θ) - F₃ = 0 → F₁ cos(θ) = 70 N
• the net vertical force is
∑ F = F₁ sin(θ) + F₂ - W = 0 → F₁ sin(θ) = 65 N
Recall that cos²(θ) + sin²(θ) = 1 for any θ, so we have
(F₁ cos(θ))² + (F₁ sin(θ))² = (70 N)² + (65 N)²
F₁² = 9125 N²
F₁ = √(9125 N²) ≈ 95.5 N
How much force is required to move a electron through an electric field with strength of 1.375 x 10^19 N/C?
Answer:
The magnitude of the force required to move the electron through the given field is 2.203 N
Explanation:
Given;
The field strength of the electron, E = 1.375 x 10¹⁹ N/C
charge of electron, q = 1.602 x 10⁻¹⁹ C
The magnitude of the force required to move the electron through the given field is calculated as follows;
F = Eq
F = (1.375 x 10¹⁹ N/C) (1.602 x 10⁻¹⁹ C)
F = 2.203 N
Therefore, the magnitude of the force required to move the electron through the given field is 2.203 N
A machine designed to stretch a stiff spring uses 1,550 J of energy to stretch the spring. If the work output is 1,200 J, what is the machine’s efficiency?
Answer:
77%
Explanation:
efficiency= work output/work input X 100%
e = 1,200j/ 1,550 j x100%
e = 1,200/1,550= 0.77
e = 0.77 x 100%
e = 77%
What is the force required to accelerate an object with a mass of 5 kg and an acceleration of
2 m/s22
Which of the following is one dimensional
A.
acceleration
B.
velocity
C.
both velocity and acceleration
D.
speed
Answer:
both velocity and acceleration
Explanation:
answer May be 3
A marble was sent down a ramp into a solo cup. The first time the solo cup moved 20 cm. The second time the solo cup moved 24 cm. The third time the cup moved 16 cm. What is the average movement of the cup?
Answer:
20
Explanation:
The average of the movement is 20+24+16/2 = 20cm
Answer:
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Explanation:
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Reflection, refraction, and diffraction
all cause light
waves to
A) bend
B) change direction
C)stand still
D)absorb energy
Answer:
B) change direction
Explanation:
Diffraction is the change of direction of waves that occurs when waves travel from one medium to another.
Reflection is the change of direction of waves when they bounce off of a barrier.
Refraction is the change of direction of waves that happens when waves pass from one medium to another.
Each of these are all the change in direction of waves.
A window cleaner has a weight of 839.86 N. The window cleaner is cleaning windows on the 4th floor of a building at a height of 12 m. How much potential energy does the window cleaner have?
Answer:
E = 10078.32 J
Explanation:
Given that,
The weight of a window cleaner, F = 839.86 N
The window cleaner is cleaning windows on the 4th floor of a building at a height of 12 m.
We need to find the potential energy of the window cleaner. We know that the potential energy of an object is given by :
E = mgh
Put values,
E = 839.86 × 12
E = 10078.32 J
So, the window cleaner will have 10078.32 J of potential energy.
Your spaceship has run out of fuel and comes to a halt halfway between the earth and the moon. Will you and your spaceship (a combined mass of 5000 kg) fall towards the moon or towards the earth? Show calculations to support your answer.
Answer:
moon
Explanation:
cause yes
Already moving at 8 m/s , wendy pushes yasmine in her sled with a diagonal 300.0 n force. th coefficient of kinetic friction between yasmine's sled and the ground is 0.30. how fast will yasmine be going after wendy pushes him for 15.00m
Answer:
You must exert a force of 4.5 N on a book to slide it across a table.
Explanation:
If 10.0 J of work are required to transfer 2.00 coulombs of
charge from point X to point Y in an electric field, what is the
difference in potential between these two points?
Answer: 5V
Explanation: because 2 goes into 10, five times. Also I know it’s correct cuz I got it right in my quiz
The difference in potential between these two points is 5 V.
Electric potential between the two points
The electric potential between two points is the work done in taking a unit postive charge from one point to another.
The difference in potential between these two points is calculated as follows;
W = qV
V = W/q
V = 10/2
V = 5 V
Thus, the difference in potential between these two points is 5 V.
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Does Ganymede have phases?
Answer:
yes An analysis published in 2014, taking into account the realistic thermodynamics for water and effects of salt, suggests that Ganymede might have a stack of several ocean layers separated by different phases of ice.
Explanation:
how can the conductivity of a semiconductor be increased?
Swampy areas can be found in many Florida locations. What weather conditions are most frequently found in this environment? *
Answer:
Heavy rain, extreme weather conditions, humid, water spouts, tornadoes, heavy lightening.
Explanation:
Swampy areas are a transition area formed where water and dry lands tend to meet. Swampy areas are actually forested areas with contains moist and humid weather conditions which has necessitated the wet soil around such an environment.
Florida is a very typical example of a weather that supports the creation of swampy areas due to its humid, heavy rains, water spouts,turnadoes etc and other extreme weather conditions.
Which is an example of a trace fossil?
animal burrow
skin of organism
preserved bone
petrified wood
Answer: The correct answer is A). Animal burrow because burrow fossils represent the preserved byproducts of behavior rather than physical remains, they are considered a kind of trace fossil. One common kind of burrow fossil is known as Skolithos, and the similar Trypanites, Ophiomorpha and Diplocraterion.
Animal burrow is an example of a trace fossil.
What is fossil?The preserved remnants of plants and animals that were submerged in sediments like sand and mud beneath ancient seas, lakes, and rivers are known as fossils. Any preserved sign of life that is typically older than 10,000 years is considered a fossil.
After death, soft body parts degrade quickly, while hard body parts, including bones, shells, and teeth, can be replaced by minerals that solidify into rock. Soft components like feathers, ferns, or other signs of life, such footprints or faeces, may also be preserved in extremely rare circumstances. Both less familiar fossils like ammonites and trilobites as well as microscopic-sized ones like single-celled foraminifera or pollen grains can be found in the remains.
What is trace fossil?A trace fossil, also known as an ichnofossil, is a record of biological activity preserved in the fossil record but without the actual preserved plant or animal remains. Contrasting with body fossils, which are the preserved remains of portions of an organism's body that were typically modified by later chemical activity or mineralization, are trace fossils. Ichnology, the study of such trace fossils, is the field of study of iconologists.
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How much voltage is required to run 0.054 A of current through a 15 2
resistor? Use AV = IR.
O A. 0.81 V
O B. 1.2 V
O c. 2.8x10²v
O D. 3.6 x 10-3 v
Answer:
The correct option is (a).
Explanation:
Given that,
Current flowing through the resistor, R = 0.054 A
Resistance of the resistor, R = 15 ohms
We need to find the voltage. We know that, Ohm's law gives the relation between voltage, current and resistance i.e.
V = IR
Put all the values,
[tex]V=0.054 \times 15\\\\V=0.81\ V[/tex]
So, the required voltage is equal to 0.81 volts.
Which choice is the BEST source of PROTEIN?
1 Meat
2 Bread
3 Rice
4 Apples
Answer: It's 1 meat.
Explanation: Meat is a protein, bread and rice are grains, Apples are fruit!
Your welcome
At an amusement park, a swimmer uses a water slide to enter the main pool If the swimmer start at rest slides without friction and descend through a vertical height of 2.31m what is her speed at the bottom of the slide
Answer:
v = 6.72 m/s
Explanation:
Given that,
Vertical height, h = 2.31 m
We need to find the speed at the bottom of the slide. Let the speed be v. We can find it using the conservation of energy such that,
[tex]\dfrac{1}{2}mv^2=mgh\\\\v=\sqrt{2gh}[/tex]
Put all the values,
[tex]v=\sqrt{2\times 9.8\times 2.31} \\\\v=6.72\ m/s[/tex]
So, her speed at the bottom of the slide is equal to 6.72 m/s.
Which of the following elements is commonly found at the core of an electromagnet?
Lead
Cobalt
Iron
If this decay has half-life of 2 years, how many years would it take for 10.8 g Protactinium-231 to remain given an initial mass of 86.3 g?
Answer:
Time = 6 years
Explanation:
First, we will calculate the no. of half life periods required to reduce the mass of Protactinium to the given value:
[tex]m' = \frac{m}{2^{n} } \\\\2^n = \frac{m}{m'}[/tex]
where,
n = no. of half-life periods = ?
m = initial mass = 86.3 g
m' = remaining mass = 10.8 g
Therefore,
[tex]2^n = \frac{86.3\ g}{10.8\ g}\\\\2^n = 8\\2^n = 2^3[/tex]
Since the bases are the same. Therefore equating powers:
n = 3
Now we calculate the time:
[tex]Time = (n)(Half-Life)\\Time =(3)(2\ years)[/tex]
Time = 6 years
NEPTUNE
•Number of days to orbit the sun:
•Distance around the sun:
Answer:
1. 165 years
2. 2.781 billion mi
Explanation:
Why should Mike repeat this investigation?
Mike needs to make sure that all the skateboards are not affected by friction.
Mike needs to have more than one set of numbers to make an accurate graph
The investigation needs multiple trials to determine which board is the control.
The investigation needs to be repeated several times to have the most accurate data.
Answer:
D
Explanation:
imagine no girls awnser this question ://
Answer:
im confused
Explanation:
How could a homework machine help students all around the world?
Answer:
Hello There!!
Explanation:
The machine can help you alot and do all your homework while you rest and let the homework machine do it and get good grades because of it with no worries but if the machine does it then you won't learn how to do them.
hope this helps,have a great day!!
~Pinky~
Identify the palindromic base sequence in the DNA donor molecule shown.
Answer the pic above
Nonsense/incorrect = auto report...
Explanation:
Since a double helix is formed by two paired antiparallel strands of nucleotides that run in opposite directions, and the nucleotides always pair in the same way (adenine (A) with thymine (T) in DNA or uracil (U) in RNA; cytosine (C) with guanine (G)), a (single-stranded) nucleotide sequence is said to be a palindrome
A 1,100kg car is going at 22 m/s. What force is needed to stop it in 20
seconds?
A 1,100 kg car is going at 22 m/s. Force is needed to stop it in 20
seconds is 1210 N.
What is force?A force is an effect that can alter an object's motion according to physics. An object with mass can change its velocity, or accelerate, as a result of a force. An obvious way to describe force is as a push or a pull. A force is a vector quantity since it has both magnitude and direction.
Using equation of motion,
v = u + at
0 = 22 + a.20
a = 1.1 m/sec²
force = mass.acceleration
force = 1100.(1.1)
force = 1210 N.
A 1,100 kg car is going at 22 m/s. Force is needed to stop it in 20
seconds is 1210 N.
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what type of charge will an object have if the object contains less protons than electrons?
Answer:
Hello, I believe it would have a negative charge considering protons have a positive charge while elctrons have a negative charge
Explanation:
What type of interference occurs when a crest and trough join?
a) Constructive Interference
b) Destructive Interference
Answer:
Destructive interference