Answer:
B
Explanation:
If the light is pointing down ,and then hits a surface of a 60 degree angle, then the direction will be away from the light since the light is touching a surface that is flat of a 60 degree angle then it will reflect off of it Perpendicular.
a truck is moving with a certain uniform velocity. it is accelerated uniformly by 0.75 m/s^2.after 20 seconds, the velocity becomes 72 km/h. find the initial velocity
Answer:
[tex]\boxed{V_{i} = 5\ m/s}[/tex]
Explanation:
Given:
Acceleration = a = 0.75 m/s²
Time = t = ?
Final Velocity = [tex]V_{f}[/tex] = 72 km/hr = 20 m/s
Required:
Initial Velocity = [tex]V_{i}[/tex] = ?
Formula:
a = [tex]\frac{V_{f}-V_{i}}{t}[/tex]
Solution:
For [tex]V_{i}[/tex] the formula becomes:
[tex]V_{i} = V_{f}-at[/tex]
[tex]V_{i}[/tex] = 20 - (0.75)(20)
[tex]V_{i}[/tex] = 20 - 15
[tex]V_{i}[/tex] = 5 m/s
In Case: If you want it in km/hr:
[tex]V_{i}[/tex] = 5 * 3.6
[tex]V_{i}[/tex] = 18 km/hr
Answer:
5 m/s
Explanation:
acceleration = 0.75 m/s²
time = 20 s
final velocity = 72 km/h = 20 m/s
initial velocity = ?
Apply formula for initial velocity.
[tex]u=-at+v[/tex]
[tex]\sf a=acceleration\\t=time\\v=final \: velocity\\u=initial \: velocity[/tex]
Solve for u.
[tex]u=-(0.75)(20)+ 20[/tex]
[tex]u=-15+20[/tex]
[tex]u= 5[/tex]
The discharge of a stream is Choose one: likely to decrease downstream in arid regions and increase downstream in temperate regions. typically lower in spring than during summer. constant for the length of the stream. calculated by dividing its cross-sectional area by its velocity.
Answer:
likely to decrease downstream in arid regions and increase downstream in temperate regions
Explanation:
Arid regions are is a region with a severe lack of water, usually to the extent that affect the organisms living in the region. Arid regions are characterized by a very low depth of rainfall per year. Temperate region on the other hand experience more distinct seasonal change and wider temperature change. Temperate regions get a fairly large amount of rainfall per year.
In arid regions, the soil is very dry, and the rate of infiltration and percolation is high relative to the amount of rainfall available. The effect is that more water is infiltrated into the soil as you move downstream, leading to a decrease in the discharge of a stream as you move downstream. Most temperate region have soils that are usually saturated in the peak of the rainfall season, leading to a greater stream discharge as you move downstream.
Ionic compounds _____.
Explanation:
Are the compounds formed by the ionic bonding or electronic bonding. They are formed by transferring the electron form one element's valance shell to other element's shell.
i hope it helps...
When a snowball turns into a puddle of
water, we know that
A. there is no change in the motion of the particles in the
puddle
B. the snowball's energy does not change; no phase change
occurs.
C. the snowball loses energy and changes from a liquid to a
solid,
D. the snowball gains energy and changes from solid to
liquid,
When a snowball turns into a puddle of water, we know that (the snow ball gains energy and changes from a solid to liquid).
This is correct due to the fact that particles of the snowball are gaining speed and so it is heating up, when the solid's temperature reaches the melting point, it will become a liquid.
Therefore, D is the correct answer.
Sally is concerned about the X-ray images her dentist plans to take of her teeth. She has read that X-rays can cause tissue effects, such as skin reddening and hair loss. Which statement would best inform Sally of the level of risk
Answer:
B. The dentist uses X-ray radiography, which takes too short a time to cause those problems.
Explanation:
The statement B would best inform Sally of the level of risk. The dentist uses X-ray radiography, which takes too short a time to cause those problems and risk.
What is X-ray imaging?X-ray imaging provides images of human internal organs. The photos depict your body parts in various colors of black and white.
Because various tissues absorb varying quantities of radiation, this is the case. Because calcium absorbs the most x-rays, bones appear white.
When X-ray radiation passes into our bodies, it damages molecular structures and may cause injury.
Human cells are damaged by extremely high doses of radiation, as indicated by skin burns, hair loss, and an increased risk of cancer.
Sally is concerned about the X-ray images her dentist plans to take of her teeth. She has read that X-rays can cause tissue effects, such as skin reddening and hair loss.
The statement B would best inform Sally about the level of risk. The dentist uses X-ray radiography, which takes too short a time to cause those problems and risk.
Hence, statement B would best inform Sally about the level of risk.
To learn more about the X-ray imaging, refer to the link;
https://brainly.com/question/27425971
#SPJ2
Calculate the speed of a car that travels 355km in 15 hours , a good answer please
Answer:
23.67 km / hr
Explanation:
car travels 355 km (d)
duration = 15 hrs (t)
average speed formula = v = d / t
v = 355 km / 15 hr
v = 23.67 km / hr
Explanation:
Hello, there!!!
Here, your question is asking about the speed and the given are:
distance (s)= 355km
time (t) = 15hrs.
speed (v)=?
now,
we have the formula:
v= s/t
or, v = 335km /15 hrs.
Therefore, the speed of car was 23.67km/hr.
Hope it helps..
how can i solve density
Answer:
p=m÷v
Explanation:
that is the formula for it. now, using your numbers p=density,m=mass and v= volume. you just divide it.
after you measurement would be in cm/3
Answer:
You can simply find density by using formula
[tex]d = \frac{m}{v} [/tex]
where m represents mass of an object and v represents volume of an object.
hope it helps..
What must be the tension of a string 202 cm long and 3 x 10-2 Kg / m per unit length (µ) for it to emit a sound of 78 Hz?
Answer:
2980 N
Explanation:
The fundamental frequency of a string is:
f₁ = √(T/µ) / (2L)
78 Hz = √(T / (0.03 kg/m)) / (2 (2.02 m))
315.12 m/s = √(T / (0.03 kg/m))
99,300 m²/s² = T / (0.03 kg/m)
T = 2980 N
Is the following nuclear reaction balanced?
Answer:
yes
Explanation:
SOMEONE HELP ME PLEASE!!!
a. What is the displacement of the car in the graph?
b. What distance has the car travelled?
Answer:
a. 2 m
b. 4 m
Explanation:
a. Assuming d is the position of the car, the displacement is the difference between the final position and the initial position. 3 m - 1 m = 2 m.
b. From t = 0 to t = 2.5, the car moves a distance of 3 m. From t = 2.5 to t = 4, the car moves another 1 m.
So the car moves a total distance of 4 m.
Which of the following would cause the force of static friction to increase?
Answer:
Answer B) An increase in [tex]\mu_S[/tex]
Explanation:
Since we are talking about the force of static friction, due to its definition as the product between the normal force to the surface times the coefficient of static friction, the only two ways such force could increase is due to an increase in the normal force, or an increase in the coefficient of static friction [tex]\mu_S[/tex].
So the only valid answer is answer B)
A river flows with a speed of 3km/h in still water. A man who can swim with a speed of 5km/h wishes to reach a point on the other bank just opposite to the starting point. In which direction should he put his strokes and how long will he take to cross the river of width 1.2km? Please try to provide a diagram and step by step explanation.
Answer:
Explanation:
Let the angle required be θ with direction opposite to current .
cos θ = 3 / 5
θ = 53° .
Resultant velocity towards the opposite side
= √ ( 5 ² - 3²)
= 4 km /h
distance covered = 1.2 km
time taken = 1.2 / 4 = .3 h
= 18 min .
The density of water is 1000 kg m^3. What is the value expressed in gcm^-3 units? please help me..
(1) 1000 (2) 100 (3) 1 (4) 0.1 (5) 0.01
Here's the neat, cool way to convert units like this:
-- 1 kilogram = 1,000 grams
-- 1 meter = 100 centimeters
So . . . . .
(1000 kg/m³) x (1000 g/kg) x (1 m/100 cm)³ =
(1,000 kg/m³) x (1,000 g/kg) x (1 m³/1,000,000 cm³) =
(1,000 x 1,000 x 1 / 1,000,000) (kg-g-m³ / m³-kg-cm³) = 1 g/cm³
A 70.0 kg skier is at rest at the top of a 120m hill. Assuming friction is negligible.
A) What is the speed of the skiers at the bottom of the hill?
Answer:
49 m/s
Explanation:
Initial potential energy = final kinetic energy
PE = KE
mgh = ½ mv²
v = √(2gh)
v = √(2 × 10 m/s² × 120 m)
v = 49 m/s
Active 13 minutes ago
6. Thrust exerted by an object of area 20 m experiencing pressure 150 Nm‐² is
a 3000 km
b. 3000 N
c. 2800 Kg
d 2800 N/m
Answer:
3000 N
Explanation:
As we know that
pressure=force/area
force=thrust
so pressure=thrust/area
thrust=pressure*area
pressure=150 Nm^-2
area=20m^2
so thrsut=150*20=3000 N
identify the motion when a car is moving with constant speed along a curve
Answer:
Uniform circular motion
Explanation:
When a car is moving with constant speed along a curve, it will said to have uniform circular motion. The speed of the car remains constant in this case. But its velocity keeps on changing. The velocity can be calculated by drawing the tangent on the circle. Hence, the motion of the car is uniform circular motion.
Answer:
Uniform motion
Explanation:
The motion when a car is moving with constant speed along a curve is an example of uniform motion.
A car moving at constant speed covers equal distances in equal intervals of time. The average speed remains the same in uniform motion.
The curve defines the path of the motion and the speed remains constant.
Is The force of friction always opposite to the motion?
Answer:
Friction force always acts tangent to the surface at points of contact. Friction force acts opposite to the direction of motion.
Explanation:
A car engine burns gas at 495 K and exhausts to the air at 293 K. What is the highest possible efficiency it could have?
(NO UNIT)
Answer:
59.19%
Explanation:
Step 1:
Data obtained from the question. This include the following:
Input temperature = 495 K.
Output temperature = 293 K.
Efficiency =..?
Step 2:
Determination of the efficiency of the engine.
Efficiency is simply defined as the ratio of output to input times 100. Mathematically, it is expressed as:
Efficiency = output /input x 100
With the above formula, we can calculate the efficiency of the engine as follow:
Input temperature = 495 K.
Output temperature = 293 K.
Efficiency =..?
Efficiency = output /input x 100
Efficiency = 293/495 x 100
Efficiency = 59.19%
Therefore, the efficiency of the engine is 59.19%
Answer:
0.41
Explanation:
Trust me bro
How much work is done when 0.0042 C is moved through a potential difference of 12.0 V? Use W = qV A. 0.050 J B. 0.00035 J C. 2900 J D. 12 J
Answer:
Work done by charge (W) = 0.050 (Approx)
Explanation:
Given:
Charge (q) = 0.0042 C
Potential difference(V) = 12.0 V
Find:
Work done by charge
Computation:
Work done(W) = qV
Work done by charge (W) = (0.0042)(12)
Work done by charge (W) = 0.0504
Work done by charge (W) = 0.050 (Approx)
Answer:
Work done by charge (W) = 0.050 (Approx)
Explanation:
Charge (q) = 0.0042 C
Potential difference(V) = 12.0 V
Find:
Work done by charge
Computation:
Work done(W) = qV
Work done by charge (W) = (0.0042)(12)
Work done by charge (W) = 0.0504
Work done by charge (W) = 0.050 (Approx)
A refrigerator recieves 240 V of electricity. If it use 32 A of current, what is the resistance of the refrigerator?
Answer:
7.5 Ω
Explanation:
Voltage = Current x Resistance
(V = IR)
240 = 32 R
R = 240 / 32
= 7.5 Ω
The power source provides a current of 1.86 A at a potential difference of 3.90 V. Calculate the power of the power source. Use the equation:
power = potential difference × current
Choose the correct unit from the box below
C W J
Answer:
W
Explanation:
The unit for Power which is (Volt X Current) is Watts. and the symbol for Watts is W.
Please help me with this question ASAP.
In a a potentiometer circuit, a 1m long potentiometer wire PQ of resistance 10 ohms is connected in series with a cells of e.m.f. 9V with internal resistance 3 ohms Calculate:
i The p.d. across PQ
ii. The e.m.f. of a cell which has a balance point of 75cm.
Answer:
i. 6.923 V
ii. The e.m.f. = 22.5 V
Explanation:
i. The given parameters are;
Length of potentiometer = 1 m
The resistance of the potentiometer = 10 Ω
The e. m. f. of the attached cell = 9 V
The current, I flowing in the circuit = e. m. f/(Total resistance)
The current, I flowing in the circuit = 9 V/(10 + 3) = 9/13 A
The potential difference, p.d. across the 1 m potentiometer wire = I × Resistance of the potentiometer wire
The p.d. across the potentiometer wire = 9/13×10 = 90/13 = 6.923 V
ii) Given that the 1 m potentiometer wire has a resistance of 10 Ω, 75 cm which is 0.75 m will have an e.m.f. given by the following relation;
[tex]\dfrac{E}{R_{balance}} = \dfrac{V}{R_{cell}}[/tex]
Where:
E = e.m.f. of the balance point cell
[tex]R_{balance}[/tex] = Resistance of 75 cm of potentiometer wire = 0.75×10 = 7.5 Ω
[tex]R_{cell}[/tex] = Resistance of the cell in the circuit = 3 Ω
V = e.m.f. attached cell = 9 V
[tex]\dfrac{E}{7.5} = \dfrac{9}{3}[/tex]
E = 7.5*3 = 22.5 V
The e.m.f. = 22.5 V
Suppose the position of an object moving in a straight line is given by s (t )equals 5 t cubed minus 2 t squared plus 9. Find the instantaneous velocity when tequals7.
Answer:
Explanation:
s(t) = 5t³-2t²+9
Instantaneous velocity v = ds / dt
v = ds/dt = 15t²-4t
Putting t = 7
v = 15 x 7² - 4 x 7
= 707
Instantaneous velocity at t = 7
is 707 unit .
Culture creates the context for behavior in society. true or false
Answer:
True every culture is diffrent and culture is the way to grow up, the people or things you live around, or the ways of life you follow or dress.
Explanation: The definition of culture is: means a particular set of customs, morals, codes and traditions from a specific time and place. All of that develops how a person may behave in society.
Answer:
true
Explanation:
just took the quiz
A mass of 1.15 kg of air at 111 kPa and 27 C is contained in a gas-tight, frictionless piston cylinder device. The air is now compressed to a final pressure of 0.84 MPa. During this process, heat is transferred from the air such that the temperature inside the cylinder remains constant. Calculate the work input (in kJ) during this process.
Answer:
Work input W = -200.39 KJ
Explanation:
From the question, we are given;
m = 1.15 kg
Constant temperature T1 = T2 = 27 + 273 = 300k
Since the temperature is constant, we can say that the process is isothermal
P1 = 111 KPa
P2 = 0.84 MPa = 0.84 * 1000 KPa = 840 KPa
Now what we want to calculate is W1-2
Mathematically, for isothermal process;
W1-2 = mRTlnP1/P2
where R can be obtained from table and it is equal to 0.287 KJ/kg.k
Hence;
W1-2 = (1.15)(0.287)(300)(ln 111/840)
W1-2 = 99.015 * -2.023871690525 = -200.39 KJ
Kindly note that the value of the work is negative because work is done on the system and not by the system
A sports car moving at constant velocity travels 120m in 5.0s. If it then brakes and comes to a stop in 4.0s,what is the magnitude of it's acceleration?
✔ First calculating the speed :
V = d(in m)/t(in s)
V = 120/5 V = 24 m/s✔ You now know the average car's speed, is time it takes to stop it completely, so you can calculate its acceleration :
a = V/t
a = -24/4 a = 6 m/s² The car has an acceleration of 6 m/s².How do you find the rest mass (kg) of a 3.1 eV electron?
Answer:
Explanation:
The rest energy of any substance is defined by the Einstein's mass energy equivalence relation. Thus the rest mass of a electron is 9.11x10^-31 kg. The speed of light is 299,792,458 m/s. Thus multiplying the square of speed of light with the rest mass of electron gives the rest energy of the electron.
Salt compounds are commonly used to melt ice that forms on sidewalks in the winter. A common chemical that is used to melt sidewalk ice is calcium chloride, CaCl2(s). When calcium chloride dissolves into solution is releases thermal energy which aides in melting
the ice.
The molar mass of water is 18.02 g/mol
The thermal energy, in kilojoules (kJ) that must be released from the calcium chloride,
CaCl2(s), to melt 10.0 kg of ice, expressed in scientific notation is a.bc x 104 k).
46
55
The values of a, b, c, and d.
Answer:
The values of a, b, c and d are
a = 3, b = 3, c = 4 and d = 3
Explanation:
The quantity of heat needed to melt the ice is given by Q = mL where m = mass of ice and L = latent heat of fusion of ice = 334 kJ/kg. This quanity of heat is also the thermal energy needed to be released by the calcium chloride, CaCl₂
Now, the mass of ice = 10 kg. So,
Q = mL
Q = 10 kg × 334 kJ/kg
Q = 3340 kJ
In scientific notation,
Q = 3.34 × 10³ kJ
So the thermal energy needed to be released by the calcium chloride is 3.34 × 10³ kJ
Comparing Q = 3.34 × 10³ kJ with a.bc × [tex]10^{d}[/tex] kJ
So, a = 3, b = 3, c = 4 and d = 3
The values of a, b, c and d are
a = 3, b = 3, c = 4 and d = 3
A hollow circular shaft made of 304 stainless steel uniformly tapers from an outer diameter of 3.0 cm to an outer diameter of 4.0 cm over a length of 2 meters. The inner diameter of 1.0 cm is constant over the length of the shaft. The shaft is subjected to an applied torque of 500 Nm. Determine the maximum shear stress in the shaft.
Answer:
maximum shear stress = τ(max) = 95.49 × 10⁶N/m²
Explanation:
given
outer diameter at one end(D₁) = 3.0cm
outer diameter at the other end(D₂) = 4.0cm
inner diameter(d₁) = 1.0cm
torque applied(T) = 500Nm
maximum shear stress will occur at lower outer diameter
the formula is τ/r = T/J
τ= T × r/J
where r is radius
T is the torque
J is the polar 2nd M of area
attached is the calculation of the question
Light travels 300 000 000 m/s and one year has approximately 32 000 000 second a light year is the distance light travels in one year
Explanation:
It is given that,
Speed of light, [tex]v=300 000 000\ m/s=3\times 10^8\ m/s[/tex]
Seconds in 1 year, [tex]t=32 000 000=32\times 10^6\ s[/tex]
We need to find the distance traveled by light in one year. Speed of an object is given by :
[tex]v=\dfrac{d}{t}[/tex]
So,
[tex]d=v\times t\\\\d=3\times 10^8\times 32\times 10^6\\\\d=9.6\times 10^{15}\ m[/tex]
Since,
[tex]1\ \text{light year}=9.46\times 10^{15}\ m\\\\1\ m=\dfrac{1}{9.46\times 10^{15}}\ \text{ly}\\\\9.6\times 10^{15}\ m=\dfrac{9.6\times 10^{15}}{9.46\times 10^{15}}\\\\d=1.01\ \text{ly}[/tex]
So, the distance covered by light is 1.01 light years.