The moon is 250,000 miles away. How many feet is it from Earth? (dimensional analysis)
Answer:
1.261 billion
Explanation:The distance between the earth and the moon in miles is 250,000,so in feet,The distance is 1.261 billion
Which of the following describes a sound wave?
A. Longitudinal wave that does not require a medium
c
B. Longitudinal wave that requires a medium
C. Transverse wave that does not require a medium
D. Transverse wave that requires a medium
49. A block is pushed across a horizontal surface with a
coefficient of kinetic friction of 0.15 by applying a
150 N horizontal force.
(a) The block accelerates at the rate of 2.53 m/s2
Find the mass of the block.
(b) The block slides across a new surface while
experiencing the same applied force as before.
The block now moves with a constant speed.
What is the coefficient of kinetic friction between
the block and the new surface?
Answer:
(a) 37.5 kg
(b) 4
Explanation:
Force, F = 150 N
kinetic friction coefficient = 0.15
(a) acceleration, a = 2.53 m/s^2
According to the newton's second law
Net force = mass x acceleration
F - friction force = m a
150 - 0.15 x m g = m a
150 = m (2.53 + 0.15 x 9.8)
m = 37.5 kg
(b) As the block moves with the constant speed so the applied force becomes the friction force.
[tex]F = \mu m g \\\\150 = \mu\times 37.5\\\\\mu = 4[/tex]
A 0.080-kg egg test dummy is fitted with a helmet and attached to a swing. This egg test dummy is pulled back and released, allowing it to collide with a cement block. The impulse on the egg test dummy is - 0.39N.s is over an interval of 0.050 s. What is the magnitude of the force on the egg test dummy during this time interval?
Answer:
7.8 N
Explanation:
Applying,
I = Ft................. Eqaution 1
Where I = Impulse on the egg test dummy, F = Force on the egg test dummy during the time interval, t = time interval
make F the subject of the equation
F = I/t.................. Equation 2
From the question,
Given: T = -0.39 N.s, t = 0.050 s
Substitute these vales into equation 2
F = -0.39/0.050
F = -7.8 N
Hence the force that act on the egg test dummy is 7.8 N
When an object is in a gravitational field, it has energy in its __________ __________ energy store.
Answer:
Gravitational potential
Explanation:
Any object that is not on the surface of the Earth, but at a height instead has potential energy. Eventually, this can become kinetic energy once the object falls.
When an object is in a gravitational field, it has energy in its gravitational potential energy store.
Compared with dim light, what do light waves that look bright tend to have the subject just says science but the picker doesn't have that
Answer:
The brightness of a light depends on the amplitude of the light wave, which is the extent the waves moves from their equilibrium position. The brightness is also related to the amount of light that is emitted or reflected by an object
Therefore, compared to dim light, light that look bright have a higher amplitude and emit or reflect more light energy (photons)
Explanation:
Can the magnitude of a vector ever (a) be equal to one of its components, or (b) be less than one of its components? 9. Can a particle with constant speed be accelerating? What if it has constant velocity?
Answer:
a) the other components are zero, in the direction of one of the coordinate axes
b) the magnitude is less than the value of one of its components, it must occur when the vector is in some arbitrary direction
9) constant velocity the acceleration must necessarily be zero,
constant speed can be accelerated since it may be changing the direction of the velocity vector
Explanation:
Vectors are quantities that have modulo (scalar) direction and sense.
a) If in a vector its magnitude is equal to one d its components implies that the other components are zero, therefore the vector must be in the direction of one of the coordinate axes
b) if the magnitude is less than the value of one of its components, it must occur when the vector is in some arbitrary direction, other than the direction of the axes, that is
R² = x² + y²
where R is the magnitude of the vector e x, and are the components
9) When a particle has a constant velocity, the acceleration must necessarily be zero,
v = vo + a t
The bold letters indicate vectors If a = 0 implies that v = vo
If a particle has constant speed it can be accelerated since it may be changing the direction of the velocity vector, this type of acceleration has the name of centripetal acceleration
when is the mass of an object if it exerts a force of 160 N and an acceleration of 8.15m/s^2
Answer:
f=ma.......m=f/a......m=20kg
Impulse can be defined as
The frequency at which something occurs
The change in velocity
The change in momentum from an force within the system
The change in momentum from a force outside of the system
Explanation:
The change in momentum from an force within the system.
Raquel establece que la rapidez del sonido en el aire en un día es de 346 m/s . Días después hace la misma medición obteniendo una rapidez de 340 m/ s . ¿Cuál será la temperatura del aire en cada día?
Answer:
La ecuación para la velodiad del sonido en aire esta dada por:
[tex]v = \sqrt{ \frac{\gamma*R*T}{M} }[/tex]
Resolviendo esto para T, obtenemos:
[tex]T = v^2*(\frac{M}{\gamma*R} )[/tex]
donde:
T = temperatura del aire en grados Kelvin
γ = constante adiabatica = 1.4
R = constante del gas ideal =
M = masa molar del aire = 29*10^(-3) kg/mol
Si sabemos que el primer día la velocidad es 346 m/s, tenemos:
v = 346 m/s
Ahora podemos reemplazar todos esos valores en la ecuación para T, y asi obtener:
[tex]T = (346m/s)^2*(\frac{29*10^{-3}kg/mol}{1.4* 8.31 J/mol*K} ) = 298.42 K[/tex]
Para el segundo día la velocidad es 340 m/s, entonces ese día la temperatura va a ser:
[tex]T = (340m/s)^2*(\frac{29*10^{-3}kg/mol}{1.4* 8.31 J/mol*K} ) = 288.16 K[/tex]
If we go on the top of the Mountain we will our weight increase or decrease?
Answer:
increase
Explanation:
guesshejwoowsnnsnakalalapqjhdjd
Answer:
our weight would decrease.
Explanation:
because of you burning all those calories and fat from hiking up the mountain.
The mass of a brick is 2kg. Find the mass of water displaced by it when it is completely immersed in water. (Density of the bricks is 2.5 g/cm^3)
Answer:
2000g
Explanation:
volume=mass/density
=2000/2.5
=800cm³
mass=density×volume
=800×2.5
=2000g
If Cl− is the only anion in the solution, what is the Cl− concentration in milliequivalents per liter?
Answer:
155mEq/L Cl-
Explanation:
A Ringer’s solution contains the following concentrations of cations: 146 mEq/L of Na+, 5 mEq/L of K+, and 4 mEq/L of Ca2+.
As Cl- is the only counterion of those cations:
For Na, the molecule is NaCl and the mEq/L of Cl- = mEq of Na+. The Cl- of the first ion is 146mEq/L Cl-
For K+, The molecule is KCl, mEq Cl- = 5mEq/L Cl-
And, for Ca2+, The molecule is CaCl2 but the equivalents of Ca2+ = Equivalents of Cl- = 4mEq/L Cl-
The total concentration of Cl- are:
146 + 5 + 4 =
155mEq/L Cl-write any two features of capital
Which statement should he place in the region marked X?
Explanation:
The answer is Electrons move between objects.
57. A red ball (m= 10 kg) is moving at 3 m/s. A green ball (m = 8 kg) is moving at 3.5 m/s. Which ball has more
energy and by how much (2)
Answer:
the green ball has 4J more energy
Explanation:
The kinetic energy is given by the formula
K = 0.5 m v^2
the kinetic energy of the red ball:
K(red) = 0.5*10*3^2= 45J
of the green ball:
K(green)=0.5*8*3.5^2 = 49J
therefore the green ball has more energy by 4 Joules
22) How is it possible to fill medicine in a syringe?explain
I hope this helps you ^-^
The acidity model given by pH = -log10[H+] where acidity (pH) is a measure of the hydrogen ion concentration [H+] (measured in moles of hydrogen per liter) of a solution. Using this model, determine the pH of a solution with a hydrogen ion concentration of 2.3 X 10^-5 (round your answer to the nearest hundredth)
Answer:
Hydrogen ion concentration, [H+] :
[tex]{ \bf{[H {}^{ + } ] = 2.3 \times {10}^{ - 5} \: mol \: l {}^{ - 1} }}[/tex]
Substitute to the negative logarithmic model:
[tex] = { \tt{ - log(2.3 \times {10}^{ - 5} ) }} \\ pH = 4.64[/tex]
Question 4(Multiple Choice Worth 3 points)
(03.02 MC)
Which statement best reflects a change in weather?
Today is cloudy, but tomorrow will be clear and sunny.
The average rainfall has decreased over the past five years.
Ocean temperatures are projected to increase over time.
Glaciers are melting more rapidly now than in the past 100 years.
plzzz helpppp asap
Answer:
a is your answer.............
can u guys help me with this question.
State one example of the cause of a short circuit. Explain your answer
Answer:
the positive and negative terminals of a battery are connected with a low resistance conductor.
List out the fundamental and derived units
a uniform meter ruler is balanced at its midpoint
Answer:
a) i) x = 0.25 m, ii) x = 0.10 m, iii) x = 0.050 m
b) i) x = 0.40 m
Explanation:
a) For this exercise we use the rotational equilibrium equation, where we assume that the anticlockwise rotations are positive.
1) L = 2W
we set our reference system in the center of the bar where the fulcrum is
∑τ = 0
W 0.50 - L x = 0
x = 0.50 W / L
we substitute the value
x = 0.50 W / 2W
x = 0.25 m
ii) L = 5W
we calculate
x = 0.50 W / 5W
x = 0.10 m
iii) L = 10 W
x = 0.50 W / 10W
x = 0.050 m
b) a new weight is placed at x₂ = 30 cm on the left side
W 0.50 + W 0.30 - L x = 0
x = (0.50 + 0.30) W / L
x = 0.80 W / L
we calculate
i) L = 2W
x = 0.80 w / 2w
x = 0.40 m
2 What are(i) free fall , (ii) acceleration due to gravity, (iii) escape velocity , (iv) centripetal force?
Answer:
Explanation:
1. Free fall implies an object falling under the gravitational influence only. During the flight, no other force acts on it except the gravitational pull.
2. Acceleration due to gravity is the earth's natural force of pull on all objects on its surface, close to its surface, or in the region where the force can be felt. This force pulls object to the surface of the earth.
3. Escape velocity is the required minimum velocity for an object to leave the gravitational influence of the earth. It has a constant value which can be determined by;
Escape velocity = [tex]\sqrt{2gR}[/tex]
where g is the gravitation force of the earth and R is the radius of the earth.
4. Centripetal force is the force of pull that is required to keep a rotation object in its curved path.
The summer camps had a field trip from the campus to Fragrance Hill. They traveled at an average speed of 65 km/h in the first 2 hours. After that, traveled at another average speed of 78 km/h. If the distance between the campus and Fragrance Hill is 364 km, what was the total time for the field trip?
Answer:
Explanation:
They traveled this distance in 2 parts, essentially. Part 1 had an average speed for a certain number of hours, part 2 had an average speed for a certain number of hours, and those 2 parts taken together took them a distance of 364 km. In equation form, that looks like this:
km/hr part 1 + km/hr part 2 = 364 km
Now we need to find each part on the left side of that equation. Part 1 first:
We traveled 65 km/hr for 2 hours, so that took us
[tex]65\frac{km}{hr}*2hr[/tex] and canceling out the hour label, we have that in part 1 we got
65(2) = 130 km. Good. Now onto the second part, where our unknown is.
We traveled 78 km/hr the second part for x hours, so that took us
[tex]78\frac{km}{hr}*xhr[/tex] and canceling out the hour label, we have that in part 2 we got
78x km. Now we can fill in the main equation (the one in bold print)
130 km + 78x km = 364 km and subtracting 130 km from both sides:
78x km = 234 km and dividing by 78 km:
x = 3 hours. Part 2 took 3 hours. Part 1 took 2 hours, so the whole trip took 5 hours.
Chỉ ra kết luận đúng trong các kết luận sau:
A.
Chỉ có các hạt mang điện tích dương chuyển động có hướng mới tạo ra dòng điện.
B.
Chỉ có các hạt mang điện tích âm chuyển động có hướng mới tạo ra dòng điện.
C.
Khi nguyên tử chuyển động có hướng thì xuất hiện dòng điện.
D.
Các dụng cụ điện sẽ hoạt động khi có dòng điện chạy qua.
An egg is dropped onto a wood floor and breaks. When a different egg (same mass) is dropped the same distance onto a foam pad on the wood floor, it does not break. Why (in terms of physics) does this happen?
A. The pad extends the time so the impulse changes.
B. An egg requires a harder surface so it won’t break.
C. The pad pulls the egg to the floor.
D. Wood is harder than the pad.
Answer:
A.
Explanation:
The pad extends the time so the impulse changes.
Answer:
A. The pad extends the time so the impulse changes
Explanation:
in term of physics it has same mass:)
In a democracy how is rule of law regarded
Answer:
It is respected as leaders are accountable to the people. The rule of law within a democratic country will dictate what actions is considered wrong and punishable to do in that country. This will prevent people from harming and violating each other to get what they want and form a stable and safe society
tìm chỉ số của A1 và A2
Answer:
A1
Explanation:
Does anyone know the answer ? I forgot my calculator.
12 x sin50
12 × sin50 = 9.192533317........
An unbalanced 6.0-newton force acts eastward on an object for 3.0 seconds. The impulse
produced by the force is
18 N:s east
2 Nós east
18 N:s west
2 Nis west
