Answer:
η = 58.8%
Explanation:
Work is defined as the force applied by the distance traveled by the body.
[tex]W =F*d[/tex]
where:
W = work [J] (units of joules)
F = force = 294 [N]
d = distance = 5 [m]
[tex]W = 294*5\\W = 1470 [J]\\[/tex]
Efficiency is defined as the energy required to perform an activity in relation to the energy actually added to perform some activity. This can be better understood by means of the following equation.
[tex]efficiency = W_{done}/W_{required}\\efficiency = 1470/2500\\efficiency = 0.588 = 58.8%[/tex]
A stone is thrown straight up. While the stone is rising:
A. its acceleration is upward and decreasing
B. its acceleration is upward and constant
C. its acceleration is upward and increasing
D. its acceleration is zero
E. None of the above.
Answer:
D. its acceleration is zero
Explanation:
Acceleration can be defined as the rate of change of the velocity of an object with respect to time.
This simply means that, acceleration is given by the subtraction of initial velocity from the final velocity all over time.
Hence, if we subtract the initial velocity from the final velocity and divide that by the time, we can calculate an object’s acceleration.
Mathematically, acceleration is given by the equation;
[tex]Acceleration (a) = \frac{final \; velocity - initial \; velocity}{time}[/tex]
In this scenario, a stone is thrown straight up. While the stone is rising its acceleration is zero because it's initial velocity is zero and it's until the stone reaches its highest point before the acceleration becomes constant and acting downward.
If a rock is dropped from the top of a tower at the front of it and takes 3.6 seconds to hit the ground. Calculate the final velocity of the penny in m/s. What is the height of the tower?
Answer:
35.28m/s; 63.50m
Explanation:
Given the following data;
Time, t = 3.6 secs
Since it's a free fall, acceleration due to gravity = 9.8m/s²
Initial velocity, u = 0
To find the final velocity, we would use the first equation of motion;
[tex] V = u + at[/tex]
Substituting into the equation, we have;
[tex] V = 0 + 9.8 * 3.6[/tex]
V = 35.28m/s
Therefore, the final velocity of the penny is 35.28m/s.
To find the height, we would use the second equation of motion;
[tex] S = ut + \frac {1}{2}at^{2}[/tex]
Substituting the values into the equation;
[tex] S = 0(3.6) + \frac {1}{2}*9.8*(3.6)^{2}[/tex]
[tex] S = 0 + 4.9*12.86[/tex]
[tex] S = 0.5 *36[/tex]
S = 63.50m
Therefore, the height of the tower is 63.50m.
what is the helmet for
Answer:
Explanation:
a helmet is used for our safety this piece of equipment is used to protect us from getting any injury's on our heads such as concussions getting a cut on your head etc.
A force of 20 N acts on an object with a mass of 5 kg. What is the acceleration of the object?
Answer:
4m/s²Explanation:
according to newton's second law of motion F=m×athus, acceleration = Force/mass= 20/5. = 4 m/s² is the total accelerationhope it helps:)
What is called gravitational potential energy?
Answer:
Potential gravitational energy is the energy that the body has due to the Earth's gravitational attraction. In this way, the potential gravitational energy depends on the position of the body in relation to a reference level.
Explanation:
How fast can Usain Bolt run if it takes him 9.9 s to run 100m?
Answer:
27.8 mph
Explanation:
May I have brainliest please? :)
A net force of 15 N is exerted on an encyclopedia to cause it to accelerate at a rate of 5 m/s2. Determine the mass of the encyclopedia.
Answer:
3 kgExplanation:
The mass of the encyclopedia can be found by using the formula
[tex]m = \frac{f}{a} \\ [/tex]
f is the force
a is the acceleration
From the question we have
[tex]m = \frac{15}{5} \\ [/tex]
We have the final answer as
3 kgHope this helps you
My Lou Vee Air Car's propeller rotates, but it does not move the car forward. Can someone please help?? This is due on Monday!
Answer:
The force to get the plane moving, and to balance the friction so it does not stop, is provided by the propeller. However, the wheels provide the acceleration of the car.
Explanation:
Snails crawl very slowly. If a garden snail crawls at 0.013 m/s north, how far will it travel in 60 seconds?
Answer:
.78 m/s north
Explanation:
Pls give brainliest if I correct
The force of 5N south acts concurrently with force of 5N 30 degrees South of East
A. Draw the diagram - TAIL to TAIL
B. Label both vectors (see page one for example)
C. Draw and LABEL the resultant and equilibrant
D.Find the magnitude and direction of the resultant and equilibrant
(scale: 1cm = 1N)
Answer:
The magnitude and direction of the resultant is 8.66 N and [tex]60^{\circ}[/tex] south of East.
The magnitude and direction the equilibrant is 8.66 N and [tex]60^{\circ}[/tex] North of West respectively.
Explanation:
Let
[tex]P=5\ \text{N}\ \text{south}[/tex]
[tex]Q=5\ \text{N}\ 30^{\circ}\ \text{south of east}[/tex]
[tex]\theta[/tex] = Angle between P and Q = [tex]60^{\circ}[/tex]
Magnitude of resultant
[tex]R=\sqrt{P^2+Q^2+2PQ\cos\theta}\\\Rightarrow R=\sqrt{5^2+5^2+2\times 5\times 5\cos60^{\circ}}\\\Rightarrow R=8.66\ \text{N}[/tex]
Direction is given by
[tex]\theta=\tan^{-1}\dfrac{Q\sin\theta}{P+Q\sin\theta}\\\Rightarrow \theta=\tan^{-1}\dfrac{5\sin60^{\circ}}{5+5\sin60^{\circ}}\\\Rightarrow \theta=30^{\circ}[/tex]
The magnitude and direction of the resultant is 8.66 N and [tex]30^{\circ}+30^{\circ}=60^{\circ}[/tex] south of East.
The magnitude and direction the equilibrant is 8.66 N and [tex]60^{\circ}[/tex] North of West.
In a lacrosse game a ball is thrown with a force of 2000 N. The throwing force acted for 0.8
seconds. If the ball had a change in velocity, Av, of 50 m/s, what is the mass of the ball?
Answer:
Mass, m = 32 kg
Explanation:
Given that,
Force, F = 2000 N
The change in velocity, (v-u) = 50 m/s
Time, t = 0.8 s
We need to find the mass of the ball. The net force acting on an object is given by :
F = ma
Where a is acceleration
[tex]F=\dfrac{m(v-u)}{t}\\\\m=\dfrac{Ft}{(v-u)}\\\\m=\dfrac{2000\times 0.8}{50}\\\\m=32\ kg[/tex]
So, the mass of the ball is 32 kg.
Which of the following statement(s) about electrical charges are correct?
A. Point charges of the same charge only attract.
B. Charged and neutral extended objects can attract.
C. Charged and neutral extended objects do not interact.
D. Point charges of the same charge only repel.
E. Extended objects of opposite charge can only attract.
F. Point charges of opposite charge only attract.
G. Point charges of opposite charge only repel.
H. Extended objects of the same charge can both repel and attract.
I. Extended objects of the same charge can only attract.
J. Extended objects of the same charge can only repel.
K. Extended objects of opposite charge can both repel and attract.
Answer:
The true statements are;
F, D, E, J
Explanation:
F and D are true because they agree with our knowledge of electrostatic interaction. Like charges repel while unlike charges attract. Statements B and C are not in line with the principles of electrostatics because neutral objects do not interact with charged bodies in an electric field.
E and J are true for the same reasons outlined above. Remember that like charges always repel each other and unlike charges always attract each other.
In a perfectly insulated container of negligible mass, 4.00 × 10−2 kg of steam at 100◦C and atmospheric pressure is added to 0.200 kg of water at 50.0◦C.
A) If no heat is lost to the surroundings, what is the final temperature of the system? B) At the final temperature, how many kilograms are there of steam and how many of liquid water?
Answer:
Following are the solution to this question:
Explanation:
Given value:
[tex]m_s= 4.00 \times 10^{-2} \ kg \\\\L_v=2256 \times 10^{3} \ \frac{J}{kg}\\\\m_w= 0.2 \ kg\\\\\Delta T= 50^{\circ}[/tex]
In point A:
[tex]Q_{Steam}=m_s \ L_v[/tex]
[tex]=0.04 \times 2256 \times 10^{3}\\\\=9.02 \times 10^4 \ J[/tex]
[tex]Q_{water}= m_w \ c_w \ \Delta T\\\\[/tex]
[tex]=0.2 \times 4190 \times 50\\\\=4.19 \times 10^4 \ J[/tex]
[tex]Q_{steam}> Q_{water}[/tex], that's why the final temperature is [tex]= 100^{\circ}[/tex]
In point B:
[tex]\to \Delta m_s L_v=m_w\ c_w \Delta T\\\\\to \Delta m_s \times 2256\times 10^3= 0.2 \times 4190 \times 50\\\\\to \Delta m_s= 1.86 \times 10^{-2} \ kg\\\\\to m_s = 2.14 \times 10^{-2} \ kg\\\\\to liquid \ left = 0.2+ 2.14 \times 10^{-2} = 2.34 \times 10^{-2} \\[/tex]
We do not use water instead of mercury in a barometer.. why.
Answer:
Required Answer:-We don't use water as Water don't expand when it came in connection of temperature.PLEASE HELP IF YOU KNOW THE ANSWER QUICK PLEASE!!!
Answer:
d
Explanation:
A motorbike is traveling to the left with a speed of 27.0 m s 27.0 s m 27, point, 0, start fraction, start text, m, end text, divided by, start text, s, end text, end fraction when the rider slams on the brakes. The bike skids 41.5 m 41.5m41, point, 5, start text, m, end text with constant acceleration before it comes to a stop. What was the acceleration of the motorbike as it came to a stop?
Answer:
Explanation:
Initial velocity , u = 27 m/s
displacement before stop, s = 41.5 m .
final velocity, v = 0
acceleration a = ?
v² = u² + 2 a s
0 = 27² + 2 x a x 41.5
a = - 27² / 2 x 41.5
= - 8.78 m /s
What is the density of a piece of quartz with a mass of 30g and a volume of 6cm^3
Answer:
[tex]\boxed {\boxed {\sf d= 5 \ g/cm^3}}[/tex]
Explanation:
Density can be found by dividing the mass by the volume.
[tex]d=\frac{m}{v}[/tex]
The mass of the quartz is 30 grams and the volume is 6 cubic centimeters.
[tex]m=30 \ g \\v= 6 \ cm^3[/tex]
Substitute the values into the formula.
[tex]d=\frac{30 \ g}{6 \ cm^3}[/tex]
Divide.
[tex]d= 5 \ g/cm^3[/tex]
The density of this piece of quartz is 5 grams per cubic centimeter.
In which of the two following cases would you recommend winnowing ?
Case 1 : when lighter part of the mixture is useful and the husk is unwanted
Case 2 : when lighter part of the mixture is unwanted and the husk is useful
[tex]{\green{\underline{\textsf{\textbf{Case 2 :When lighter part of a mixture is unwanted and the husk is useful. }}}}}[/tex]
[tex]{\green{\underline{\textsf{\textbf{Explanation : }}}}}[/tex]
As we know that, Winnowing is used when the lighter particles is required to remove. Hence, in Case 2 the lighter part is removed and the remaining is needed.
The photo shows two yeast cells. Each cell is an individual organism. Which sentence best describes what happened to each cell during cell growth?
A. It will become many different cells.
B. It will produce offspring with a mate.
C. It will divide in half to form two new cells.
D. It will become larger by taking in nutrients.
The answer is option c - It will divide in half to form two new cells..
Explanation:
The sentence that best describes what happened during cell growth is ;
( D ) It will become larger by taking in nutrients
As the yeast cells begin to grow ( i.e. cell growth ), they will require more nutrients and as they take in the necessary nutrients they will gradually increase in size ( becoming larger ) which is a vital sign of cell growth and development, which will be seen in the yeast cells as they undergo cell growth.
The production of offsprings with a mate does not describe an activity that occurs in cell growth.
Hence we can conclude that The sentence that best describes what happened during cell growth is, It will become larger by taking in nutrients.
Learn more : https://brainly.com/question/24893507
8. An object has a force applied. The object has a mass of 36 Kg and accelerates at 3.4 m/sec2. What is the force acting on the object? *
a. 120.6 N
b. 126.9 N
c. 122.4 N
d. 118.3 N
Answer:
122.4
Explanation:
A tennis ball is beaten downward with an initial speed of 5 m/s.
How fast, in m/s, is the ball falling after 3 seconds (neglect air
friction, so g = 9.8 m/s2)?
a 34.4
b 34.4
C 9.8
d 9.8
e 5
Answer:
34.4m/sExplanation:
Step one:
given data
initial speed u= 5m/s
time t= 3seconds
acceleration due to gravity g= 9.8m/s^2
Required:
the final velocity v
Step two:
applying the first equation of motion
v=u+gt-----------we used + because the ball is falling with gravity
v=5+9.8*3
v=5+29.4
v=34.4
The final velocity is 34.4m/s
Answer:
-34.4
Explanation:
the person above had the right approach but it would be negative as it is in a downwards motion
Why is the Earth generally warmer at the equator than at the poles?
Answer: The Sun's energy is more concentrated on the equator than the poles. This is because the Sun's energy (in the form of warmth) is more direct at the equator, and less direct at the poles.
Explanation: You can see this with a flashlight. When you point the flashlight directly toward a tale, the light is very concentrated and right. However, when you point the flashlight toward the table at an angle, the light becomes more spread out and less concentrated. This is why even though sometimes the North Poles and South Poles have 24 hours of sunlight, it never actually reaches a high temperature and instead, keeps it's cold temperature.
The speed of sound through air is approximately 340 m/sec. What is the wavelength of a sound wave with a frequency of 706 Hz? Round to the nearest hundredth
Answer:
Wavelength = 0.48 m (Approx)
Explanation:
Given:
Speed of sound = 340 m/s
Frequency = 706 hz
Find:
Wavelength
Computation:
Wavelength = Speed of sound / Frequency
Wavelength = 340 / 706
Wavelength = 0.48 m (Approx)
please help!!!!!!!!!!
Answer:
C
Explanation:
three bricks means 3 times the weight, so 6/3=2
10. Scientists created models that show a rocky asteroid crashing into a moon (less mass) a
planet (more mass). In both crashes, the asteroid was the same mass. Scientists want to kno
happened to the asteroid. Use the information in the diagram to answer.
In which crash did the asteroid experience a stronger force? How do you know?
a
Crash 2; the force on the planet was stronger in this crash, so the force on the astero
also stronger.
There was no force on the asteroid. Only the moon and planet experienced a force in
Answer:
The diagram doesn’t tell you anything about the force on the asteroid. It only gives information about the force on the planet and the moon.
Explanation:
La motocicleta que tiene el récord mundial de aceleración es una motocicleta eléctrica, llamada "Killacycle" la cual permite pasar de 0 Km/h a 100 km/h en tan solo 1.5 s ¿Cuál es la aceleración media de esta motocicleta?
Answer:
[tex]a=18.51\ m/s^2[/tex]
Explanation:
Given that,
Initial speed, u = 0 km/h
Final speed, v = 100 km/h = 27.77 m/s
Time, t = 1.5 s
We need to find the average acceleration of this motorcycle. It is equal to the rate of change of velocity and it is given by :
[tex]a=\dfrac{v-u}{t}\\\\a=\dfrac{v}{t}\\\\a=\dfrac{27.77\ m}{1.5\ s}\\\\a=18.51\ m/s^2[/tex]
So, the acceleration of the motorcycle is [tex]18.51\ m/s^2[/tex].
how much force must be applied to accelerate a 3 kg remote control car from rest to 10 m/s in 5 seconds
Explain why when a firefighter rescues a dog that has fallen through ice on a
lake, they put their ladder on the ice first and then crawl out to the dog on the
ladder.
Answer:
This can spread their weight.
Explanation:
The ladder has a much larger surface area than the firefighter. Hence, his weight is spread out much more than usual, decreasing the pressure on the ice, preventing the ice from breaking/cracking.
Hope this helped!
angela runs and slides across an icy path in her driveway. she comes to a stop because of friction. which free-body diagram shows her while she is sliding?
Answer: C
Explanation: You always have weight pushing down and natural force pushing up to neutralize those forces. The you add in friction and that’s how you find the answer. Plus I got it right in my quiz
Please help anyone it would mean a lot and read the question !!