Answer:
A. The reactions taking place in a cold pack
Explanation:
This is because in a cold pack, there is no heat gained therefore a reaction stands by losing it's own heat to the surrounding.
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A child throws a tennis ball straight down with a speed of 14.8 m/s. It takes 1.5 seconds to reach the ground. What is its velocity when it reaches the ground?
Answer:
-14.8 m/s
Explanation:
Unless this is a trick question the initial velocity is 14.8 m/s. Velocity is a vector quantity, i.e. it has a magnitude AND direction. Speed which is a scalar is certainly 14.8 m/s. The direction of the vector depends on the axis of co-ordinates chosen; consequently velocity might be said to be - 14.8 m/s
Driving home from school one day, you spot a ball rolling out into the street . (See the figure below) You brake for 1.50 s , slowing your 950-kg car from 16.0 m/s to 9.50 m/s.
a)What was the magnitude of the average force exerted on your car during braking?
b)What was the direction of the average force exerted on your car during braking?
c)How far did you travel while braking?
Answer:
a) 4116.67 N
b) negative (assuming car is traveling in positive direction)
c) 19.125 m
Explanation:
Part A)We can find the average force exerted on the car by using Newton's 2nd Law: F = ma.
We have the mass (950 kg) but we do not have the acceleration. Let's solve for this using kinematics.
We have the time during braking, the initial and final velocity, and we need to find the acceleration. To do this, we can use the following equation: v = v₀ + at.
v (final velocity) = 9.50 m/sv₀ (initial velocity) = 16.0 m/st (time) = 1.50 s a = ?Substitute these values into the equation.
v = v₀ + at9.50 m/s = 16.0 m/s + a (1.50 s) 9.50 = 16.0 + 1.50a -6.50 = 1.50a a = -4.333333... m/s²The car's acceleration during the braking period is -4.33 m/s², assuming the car is traveling in the positive direction.
Now, we can use this to plug into Newton's 2nd Law to find the force exerted on the car.
F = maF = (950 kg) (-4.33...) F = -4116.666667 NThe magnitude of the average force exerted on the car while braking is the absolute value, so it is 4116.67 N.
Part B)The direction of the average force is denoted in the negative sign. It is opposite the direction of the car's motion. Assuming that the car is traveling in the positive direction, the direction of the average force exerted on the car is in the negative direction since this force is slowing the car down while braking.
Part C)We can find the distance traveled during the braking period by using another kinematic equation.
We have the initial and final velocity, and the time traveled, so we can use this equation: Δx = v_avg · t.
Note that v_avg is the same thing as (v + v₀) / 2.Substitute the known values into the equation.
Δx = [(9.50 + 16.0)/2] · 1.50 Δx = 12.75 · 1.50Δx = 19.125 mThe car traveled 19.125 m while braking.
Select the best answer for the question.
17. How many mL of HEPARIN 10,000 units/mL are needed for a 7,000 unit dose?
O A.0.7
O B. 0.07
O C.7
O D. 0.007
0.7 mL of HEPARIN 10,000 units/mL is needed for a 7,000 unit dose.
To calculate the volume of HEPARIN 10,000 units/mL needed for a 7,000 unit dose, we can use the formula:
Volume (mL) = Dose (units) / Concentration (units/mL)
Given that the dose is 7,000 units and the concentration of HEPARIN is 10,000 units/mL, we can plug these values into the formula:
Volume (mL) = 7,000 units / 10,000 units/mL
Volume (mL) = 0.7 mL
So, 0.7 mL of HEPARIN 10,000 units/mL is needed for a 7,000 unit dose. However, none of the provided answer choices match exactly with 0.7 mL. The closest option is B. 0.07 mL, which is one-tenth of 0.7 mL. Therefore, the correct answer is B. 0.07 mL.
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what is suvat in physics ?
is lightning man-made or Natural occuring?
claim:
give scientific reason:
evidence:
Answer:
give me brainliest
Explanation:
Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions, both in the atmosphere or with one on the ground, temporarily equalize themselves, causing the instantaneous release of as much as one gigajoule of energy. ... Humans have deified lightning for millennia.
Lightning happens when the negative charges (electrons) in the bottom of the cloud are attracted to the positive charges (protons) in the ground.
A human hair is approximately 50 pm in diameter. Express this diameter in meters.
A human hair is approximately 50 μm = 5 × 10⁻⁵ m in diameter
write any three differences between metals and nonmetals
Metals Non-metals
They are solid at room temperature. They may be solid, liquid and gas at room temperature.
They have high melting and boiling points. They have low melting and boiling points.
They are good conductors of heat and electricity. They are bad conductors of heat and electricity.
What is the velocity of an object that moves from 73 m to 62 m in 15 s?
Answer:
Below
Explanation:
You can use this formula to find the velocity of an object
velocity = displacement / change in time
For this problem, we need to find displacement first
To find displacement all you need to do is find the difference between the two distances!
So our displacement here would be
73 - 62 = 11 m
Now that we have displacement we can find velocity
velocity = 11 / 15
= 0.733333....
= 0.73 m/s
Hope this helps! Best of luck <3
The velocity of an object that moves from 73 m to 62 m in 15 s is 0.73 m / s.
What is velocity?When an item is moving, its velocity indicates how quickly its location is changing as seen from a specific point of view and as measured by a specific unit of time.
If a point travels a specific distance along its path in a predetermined amount of time, its average speed throughout that time is equal to the traveled distance divided by the travel time. For instance, a train traveling 100 km in two hours is moving at an average speed of 50 km/h.
Given:
The distance of the object = 73 m to 62 m,
The time taken by the object, t = 15 s,
Calculate the displacement of the object = 73 - 62 = 11 m
Calculate the velocity by the formula given below,
[tex]v = d /t[/tex]
v = 11 / 15
v = 0.73 m / s
Therefore, the velocity of an object that moves from 73 m to 62 m in 15 s is 0.73 m / s.
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The average speed, correspondence to the average speed in a trajectory. True or false?
Answer:
hablo españolete telo ease
Explanation:
astone is thrown upwards with an initial velocity of 25m/s at ange of 30 to the ground. work out the stones horizantal range?
Explanation:
[tex]R = \dfrac{v_0^2}{g}\sin{2\theta} = \dfrac{(25\:\text{m/s})^2}{9.8\:\text{m/s}^2}\sin{60°}[/tex]
[tex]\:\:\:\:=55.2\:\text{m}[/tex]
If a body travels 18 km in 1 hrs, find the average velocity of the body in m/s
Answer:
Explanation:
18 km/hr (1000 m/km)(1 hr/3600 s) = 5 m/s
Explain why selling cereal by mass rather then by volume be more fair to customers
Answer:
Simple, there could be air in the package and volume would record that, whereas mass would count the mass of the cereal and discount the air.
A small piece of aluminum (atomic number 13) contains 10^15 atoms (The atomic number is the number of protons; it determines the (positive) electric charge of the nucleus and, thus, the number of electrons in a neutral atom.) If the piece of aluminum has a net positive charge of 3.0 uc what fraction of the electrons that the aluminum had when it was neutral would have had to be lost?
Answer:
3 micro coulombs = 3 * 10E-6 coulombs charge of aluminum
13 * 10E15 * 1.6 * 10E-19 = 2.08 E-3 Coulombs - charge of atoms in Al
3 * 10E-6 / 2.08 * E-3 = 1.44 * E-3 = .00144 = .144 %
.00144 of the original electrons would have to be lost
b. What is measurement? Why measurement is important in our daily life? 3 Write the sunits of electric current and
Explanation:
Please mark me as brainlyest
Answer:
- Measurement is a comparison of an unknown quantity with a known fixed quantity of the same kind. The value obtained on measuring a quantity is called its magnitude. Magnitude of a quantity is expressed as numbers in its units.
- Measurements play an important role in daily life because they are useful to do basic tasks, such as take a child's temperature with a thermometer, make time estimations, measure out medicine and find weights, areas and volumes of different materials or substances.
- Electrical Parameter Measuring Unit Unit/Symbol
Voltage Volt V or E
Resistance Ohm R or Ω
Current Ampere I or i
Capacitance Farad C
Explanation:
I'm not sure but hope it helps.
If the toy car weighs 250g and has a kinetic energy of 2.0 J, what is its velocity
Explanation:
Kinetic energy (J) = 2j
mass= 250g
velocity=?
1kg=1000g
mass= 250/1000
mass=0.25kg
Kinetic energy (J) = ½ x mass (kg) x [velocity]² (m/s)
2=1/2 × 0.25× [velocity]²
2=0.125× [velocity]²
[velocity]² = 2/0.125
[velocity]²=16
velocity= (16)^1/2
velocity= 4 m/s
A spring with spring constant 120 N/m and unstretched length 0.4 m has one end anchored to a wall and a force F is applied to the other end.
Required:
a. If the force F does 250 J of work in stretching out the spring, what is its final length?
b. If the force F does 250 J of work in stretching out the spring, what is the magnitude of F at maximum elongation?
(a) The work done by F in stretching the spring a distance x is
W = 1/2 (120 N/m) x ²
so F performs 250 J of work on the spring, then
250 J = 1/2 (120 N/m) x ² ==> x ² ≈ 4.17 m² ==> x ≈ 2.04 m
(b) In order for F to perform 250 J of work, its magnitude must be
F = (120 N/m) (2.04 m) ≈ 245 N
principle of electroplating
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Answer:
Electroplating is the method of depositing one metal over another in the presence of a metal salt (in aqueous solution). The water molecule is released as the final product in this process. As a consequence, electroplating is based on the theory of hydrolysis.
A student is making a model of the famous Giza pyramid,
which has four triangular sides and a square base. The
scale of the model is 1:1,000.
How many sides should the model pyramid have?
Answer:
The Great Pyramid of Giza (also known as the Pyramid of Khufu or the Pyramid of Cheops) is the oldest and largest of the pyramids in the Giza pyramid complex bordering present-day Giza in Greater Cairo, Egypt.It is the oldest of the Seven Wonders of the Ancient World, and the only one to remain largely intact.
Explanation:
plzzzzzzzzzzzz somebody help, plzzzzzzzz this is important. where are the geniuses out there please help. Thanks in advance .
Four forces act as shown in the
diagram below, calculate their
resultant.
12N
10N
40
30
60°
15N
9N
iAnswer:
The resultant vector force = 6.96i - 9.27j
The magnitude = 11.6N
The direction= -53.1 °
Explanation:
i= 10×cos(30) + 15×cos(-60) + 9×cos(-90) + 12×cos(140) = 6.96
j= 10×sin(30) + 15×sin(-60) + 9×sin(-90) + 12×sin(140) = -9.27
The type of force that will not cause a change in the speed of an object.
Explanation:
Balanced forces will cause no change in the speed of an object.
Lithium's atomic number is 3. How many electrons does a neutral lithium atom have? explain.
Answer:
It has 3 electrons
Explanation:
Neutral atom has an overall charge of zero.
Since atomic number is 3, it has 3 protons [ positive charges ]. So, to be neutral, the atom must have 3 electrons [ negative charges ] to cancel out the positive charge.
An 8-ohm resistor is connected to a 120-volt circuit. What current will it draw?
Answer:
15 A (15 amperes of current)
Explanation:
From Ohm's Law,
Voltage, V = Current, I × Resistance, R
Making Current, I the subject:
Current, I = Votage, V/ Resistance,R
= V/R
= 120volts /8ohms
= 15 A
Pls help lsplsplsplsplsplsplsplps
hey there! the correct answer would be ozone! hope this helps!!
Which of the following is an example of a physical change?
Burning charcoal.
Dissolving sugar in water.
Cooking a hamburger.
Car Rusting.
Answer:
Dissolving sugar in water is an example of a physical change .
.......
Carnot Engine: A Carnot cycle consists of 179) A) four adiabats. B) two adiabats and two isobars. C) four isotherms. D) two adiabats and two isotherms. E) two isobars and two isotherms
Answer:
which question is this
Explanation:
I don't understand sorry
For an electron, magnitude of force on it
is
Select one
• Bev
bev
Be
BIL
Answer:
F = Bev
Explanation:
B is magnetic field density
e is the electron charge
v is the electron velocity
What is the amount of force exerted by gas particles?
Answer:
Pressure is the force divided by the area on which the force is exerted, and temperature is measured with a thermometer. We gain a better understanding of pressure and temperature from the kinetic theory of gases, which assumes that atoms and molecules are in continuous random motion.
Who has greater displacement, an astronaut who has just completed an orbit of the earth or you when you have just traveled from home to school?
Answer:
Explanation:
This is going to sound like an absurd answer, but sometimes physics can be a little strange.
This answer is weird because of the definition of displacement. It means the distance from the starting point to the ending point, disregarding what happened in between. The point is that the astronaut is at the starting point of his orbit. By definition the starting and ending points are the same. His displacement is 0.
So the answer is you have the greater displacement when you walked one way to school. The starting point and the ending point are different. You have gone further.
However just to make things a little nasty, when you walk home again, your displacement will be the same as the astronaut's -- 0 meters because you will be right back where you started from.
You that just traveled from home to school has greater displacement than the astronaut.
Displacement is defined as the change in the position of an object.
An astronaut who completed an orbit of the earth, has moved from an initial position x₁ and returned to the same position x₁ because Earth is assumed to be spherical. To complete an orbit of the Earth, the astronaut must return to his initial position since he will move round the Earth.
The displacement of the astronaut is zero because x₁ - x₁ = 0
For you that have just traveled from home to school, BUT haven't returned, your displacement is greater,.
Let's say the distance from your home to school = y
Your initial position at your home = 0
your displacement = y - 0 = y
Thus, you that just traveled from home to school has greater displacement than the astronaut.
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An electromagnetic wave from space is detected with a frequency of 4.4 x 109 Hz. What is the wavelength of this wave?
Explanation:
[tex]\lambda = \dfrac{c}{\nu} = \dfrac{3×10^8\:\text{m/s}}{4.4×10^9\:\text{Hz}} = 0.068\:\text{m}[/tex]
Bradd stands 6km west of a flagpole, and runs towards it with a speed of 9km/h. Pitt stands 5km east of the flagpole, and runs towards it with a speed of 8km/h. At what displacement from the flagpole are they when they meet?
Answer:
176 m west of the flagpole.
Explanation:
In exact and precise interpretation of the question the answer is 0 m as they would both crash into the pole when they got there and presumably stop having suffered broken noses and serious groin injuries.
However my GUESS as to the intent of the question is that the first to reach it will sidestep the flagpole slightly and continue on their current path until they meet and slap a high five as they pass one another.
In that case, they have 6 + 5 = 11 km to traverse at a closing rate of 9 + 8 = 17 km/hr.
They will meet in 11 km / 17 km/hr = 0.647 hrs
Bradd will have covered 9 km/hr(0.647 hr) = 5.823 km
meaning that they will be 6 - 5.823 = 0.176 km or 176 m west of the flagpole.
Pitt will have covered 8 km/hr(0.647 hr) = 5.176 km
meaning they will be 5 - 5.176 = - 0.176 km east which equals 0.176 km west of the flagpole