Answer:
[tex]8.0\; \rm J[/tex].
Explanation:
The efficiency of a machine is the ratio between the useful output and the energy input:
[tex]\begin{aligned}\text{efficiency} &= \frac{\text{useful output}}{\text{energy input}} \times 100\%\end{aligned}[/tex]
Rearrange this equation to find energy input in terms of efficiency and useful output:
[tex]\displaystyle \text{energy input} = \frac{\text{useful output}}{\text{efficiency} / (100\%)}[/tex].
Substitute in the values: [tex]\text{useful output} = 1.2\; \rm J[/tex] and [tex]\text{efficiency} = 15\%[/tex]. Evaluate to find the value of [tex]\text{energy input}[/tex]:
[tex]\begin{aligned} \text{energy input} &= \frac{\text{useful output}}{\text{efficiency} / (100\%)} \\ &= \frac{1.20\; \rm J}{15\% / (100\%)} \\ &= 8.0\; \rm J\end{aligned}[/tex].
(Rounded to two significant figures as in the value of efficiency.)
A ball is thrown from ground level at an angle of 0 and the initial velocity components are 7.5m/s and 13m/s. Ignoring air resistance, calculate each of:
1- The initial velocity is vi
2- The value of the angle at which the ball was thrown
3 - The horizontal range of the ball R
I assume you mean an angle of θ, and not 0. I also assume the given components of the initial velocity are horizontal and vertical, respectively, so that
1. the initial velocity vector is
[tex]\boxed{\vec v_i = (7.5\,\vec\imath + 13\,\vec\jmath) \dfrac{\rm m}{\rm s}}[/tex]
which means the ball is thrown with an initial speed of
√((7.5 m/s)² + (13 m/s)²) ≈ 15 m/s,
and
2. the angle made by [tex]\vec v_i[/tex] with the positive horizontal axis is θ such that
[tex]\tan(\theta) = \dfrac{13}{7.5} \implies \theta \approx \arctan(1.7) \approx \boxed{60^\circ}[/tex]
3. At time t, the ball attains a height y and horizontal range x according to
y = (13 m/s) t - g/2 t²
x = (7.5 m/s) t
where g = 9.8 m/s². When the ball reaches the ground (y = 0) for t > 0, we have
(13 m/s) t - g/2 t² = 0
13 m/s - g/2 t = 0
t = 2 (13 m/s)/g = (26 m/s)/g
Plugging this time into the x equation gives a horizontal range of
x = (7.5 m/s) (26 m/s)/g ≈ 20. m
Daniel is 50.0 meters away from a building. He observes that his line-of-sight to the tip of the building makes an angle of 63.0° with the horizontal. What is the height of the building?
Answer:
willie tower
Explanation:
mataas kasi
plz help will mark brainliest
Explanation:
The rod can be in equilibrium only if the resultant force is 0 and the moment around any point of the rod must be equal to 0.
We have to take moments around the pivoted point.
Moment = Force × Perpendicular distance to the force
For the rod to be in equilibrium,
Clockwise moment - Anticlockwise moment = 0
Clockwise moment = Anticlockwise moment
The distance between pivoted point and the weight of rod = 50 cm - 30 cm = 20 cm
So 20 cm× 1.2 N produces a Clockwise moment
If Perpendicular distance between pivoted point and 2N load is x,
Anticlockwise moment = x × 2N
20 cm× 1.2N = 2N × x
x = 12 cm
So 2 N load is at 12 from the pivoted point.
From the left edge of the meter ruler, 2N load is at 30-12 cm distance
= 18 cm
Answer: 18 cm
Explanation:
As an aeroplane decelerates, its kinetic energy decreases. Suggest what happens to this energy
they are converted into thermal and sound energy as well as the kinetic energy in the air
The main goal of every defense is to __________. A. stop the ball B. regain possession of the ball C. protect the goal or basket D. all of the above
Answer:
D.
Explanation:
I believe it is D. Because in defense you are to stop others from scoring, while trying to score. But also while trying to protect the Goal or basket. I hope this helps you out.
Answer:
d
Explanation:
I’m not sure what this is… help please
Answer:
A) Slower
Explanation:
Less / low energy means less / slower speed.
Have a nice day!
I hope this is what you are looking for, but if not - comment! I will edit and update my answer accordingly. (ノ^∇^)
- Heather
A bob attached to a string of length L = 1.25 m, initially found at the equilibrium
position, is given an initial velocity v = 0.8 m/s. The maximum displacement angle,
Omax, is: (Take g=10 m/s)
17
3.2
13
10.2
6.4
Clear selection
A hoh attached to a string of length 2 m is displaced by an angle of 8º and then
The maximum displacement angle of the bob is 13⁰.
The given parameters;
Length of the pendulum, L = 1.25 mInitial velocity of the bob, v = 0.8 m/sThe maximum displacement of the bob is calculated by applying the principle of conservation of energy;
[tex]P.E = K.E\\\\mgh = \frac{1}{2} mv^2\\\\h = \frac{v^2}{2g} \\\\h = \frac{0.8^2}{2\times 10} \\\\h = 0.032 \ m[/tex]
The maximum displacement angle is calculated as follows;
[tex]cos \theta = \frac{L-h}{L} \\\\cos \theta = \frac{1.25 - 0.032}{1.25} \\\\\cos \theta = \frac{1.218}{1.25} \\\\cos \theta = 0.9744\\\\\theta = cos^{-1}(0.9744)\\\\\theta = 13\ ^0[/tex]
Thus, the maximum displacement angle of the bob is 13⁰.
Learn more here:https://brainly.com/question/13981780
HELP
How much heat energy is required to raise the temperature of 37.5g of water from 23.0°C to 55.2°C? The specific heat for water is 4.184 J/g°C. (Include your calculation to receive credit.)
Answer: 5.05 J
Explanation:
Qcalorimeter: m*c* ΔT --> (37.5g)*(4.184J/g ° C)*(55.2 °C – 23.0 °C) Qcalorimeter: 5.05 J
According to specific heat capacity, 5.052 kJ of heat energy is required to raise the temperature of 37.5 g of water from 23.0°C to 55.2°C.
What is specific heat capacity?Specific heat capacity is defined as the amount of energy required to raise the temperature of one gram of substance by one degree Celsius. It has units of calories or joules per gram per degree Celsius.
It varies with temperature and is different for each state of matter. Water in the liquid form has the highest specific heat capacity among all common substances .Specific heat capacity of a substance is infinite as it undergoes phase transition ,it is highest for gases and can rise if the gas is allowed to expand.
It is given by the formula ,
Q=mcΔT
Substitution in above formula, givesQ= 37.5×4.184×32.2=5052.18 J or 5.052 kJ.
Thus , 5.052 kJ of heat energy is required to raise the temperature of 37.5g of water from 23.0°C to 55.2°C.
Learn more about specific heat capacity,here:
https://brainly.com/question/28941910
#SPJ2
Déterminer la charge de noyau d’atome d’oxygène en coulomb C
Answer:
determine a large mam I have no idea
Definition of Speed?
speed- the rate something moves or operates
Can I have brainlist please
The Speed are distance covered by the object in unit time.The S.I unot of speed is metre per second written as m/sec.It is a scalar quantity.
Speed=Distance/TimeAverage speed=Total distance covered/Total time takenThe speed is measured in metres per second ( ms- ¹ )
Where denoted by s
The distance travelled is measured in metres (m) and denoted by d
t is the amount of time spent and measured in seconds s
Explanation:There are Two Types of Speed are :Uniform Speed: When the distance travelled by a body is equal in equal interval of time then the speed is uniform. Non-uniform Speed: When the distance travelled by a body is unequal in an equal interval of time then the speed is known as non- uniform speed.There are four different forms of speed are : If an object travels the same distance in the same amount of time, it is said to be moving at a uniform speed.When an object travels a different distance at equal intervals of time, it is said to be moving at variable speed.The Average speed is the average speed determined by the ratio of the total distance travelled by an object to the entire amount of time it took to travel that distance.The speed of an object at any given moment when it is travelling at a variable speed is referred to as the object's instantaneous speed.Know more:The Discover of the Speed is Galileo Who was the Discover the speed as the distance covered per unit of time.Speed is measured as the ratio of distance to the time in which the distance was coveredThe dimensional formula of speed is:M ⁰ L ¹ T -¹ The measurement of speed in vehicles, speedometers are used. To measure the distance covered odometers are used. The Speed can also be calculated with the help of a graph. The Distance-time graph helps in understanding the speed of an object.An instrument to measure immediate speed is a speedometer.186,282 miles per second is another way to write the speed of light.In dry air, the speed of sound is 343.2 meters per second.A ball is projected at an immovable wall with a speed vi and bounces back the wall in such a manner that it only has 1/3 of its original linear momentum. a) Determine what fraction of the kinetic energy is lost in the collision.
The fraction of the kinetic energy of the ball lost during the collision is [tex]\frac{1}{3}[/tex].
The given parameters;
initial speed of the ball, = vifinal momentum of the ball, Pf = ¹/₃PiThe initial and final momentum of the ball is calculated as;
[tex]P_i = m_ivi[/tex]
[tex]P_f = m_fv_f = \frac{1}{3} m_iv_i[/tex]
The initial and final kinetic energy of the ball is calculated as;
[tex]K.E_i = \frac{1}{2} m_iv_i^2 = \frac{1}{2} P_iv_i\\\\K.E_f = \frac{1}{2} m_fv_f^2= \frac{1}{2} (\frac{1}{3} P_iv_i)= \frac{1}{6} P_iv_i[/tex]
The change in the kinetic energy is calculated as;
[tex]\Delta K.E = K.E_f - K.E_i \\\\\Delta K.E = \frac{1}{6} P_iv_i - \frac{1}{2} P_iv_i = \frac{1}{3} P_iv_i[/tex]
Thus, the fraction of the kinetic energy of the ball lost during the collision is [tex]\frac{1}{3}[/tex].
Learn more here:https://brainly.com/question/18566218
PLEASE ANSWER NEED HELP!!!!!!!! PLEASE THE CORRECT ANSWER!!!!!!
Medicine in Western cultures has not focused on the energy in the body as much as cultures in Asia have.
A.
True
B.
False
PLEASE NO LINKS
Answer:
A
Explanation:
This is true because culture in Asia focus more on energy that is why we see kung fu and taekwondo etc.
Answer:
A
Explanation:
Got it right.
PLEASE ANSWER NEED HELP!!!!!!!! PLEASE THE CORRECT ANSWER!!!!!!
Reba knows that if she exercises it will help her body, but she is less sure how this will bring positive changes to other aspects of her life. What is the BEST way to explain this connection to Reba?
A.
When you are healthy, everything is automatically better.
B.
Exercise will lead her to meditate, allowing her to improve her mind and body.
C.
She will definitely lose a lot of weight, and thinner people are always happier.
D.
Exercise reduces stress and boosts confidence, which can create positive change.
PLEASE NO LINKS OR I WILL REPORT YOU
D.
Exercise reduces stress and boosts confidence, which can create positive change.
what are some things to keep in mind before and while playing volelyball
Heat rising in a hot-air balloon is an example of __________.
A potted plant falls from the window of an apartment building. It falls for 2.0
s and then hits the ground. What is the speed of the plant just before it hits
the ground? Assume only gravity is acting on it.
A)20 m/s
B) 9.8 m/s
C) 2.0 m/s
D) 4.9 m/s
Answer:
D) 4.9 m/s
Explanation:
Speed of Object in Free Fall
s = Rate of Acceleration, Due to Gravity × Length of Time
s = 9.8 × 2.0
s = m/s (Round Up to The Nearest Whole Number)
--
m/s = 9.8 ÷ 2.0 = 4.9 m/s
A 2 kg object has a specific heat capacity of 1,700 J/(kg \cdot⋅oC)
To raise this object's temperature from 15 Celsius to 25 Celsius, the object must absorb _______ Joules of heat.
The amount of heat needed to raise the temperature of a 2kg object from 15°C to 25°C is 34000J.
HOW TO CALCULATE SPECIFIC HEAT CAPACITY:
The amount of heat absorbed by an object can be calculated by using the following expression:Q = m.c.∆TWhere;
Q = amount of heat absorbed or released (J)m = mass of objectc = specific heat capacity (J/g°C)∆T = change in temperature (°C)According to this question, 2 kg object has a specific heat capacity of 1,700J/kg°C and was raised from a temperature of 15 Celsius to 25 Celsius. The heat absorbed is calculated as follows:Q = 2 × 1700 × {25 - 15}Q = 3400 × 10Q = 34000JTherefore, the amount of heat needed to raise the temperature of a 2kg object from 15°C to 25°C is 34000J.Learn more about how to calculate heat absorbed at: https://brainly.com/question/11194034?referrer=searchResults
A fairly efficient steam turbine engine fired by coal is used to drive an electric generator. The generator operates between 2100°C and 385°C.
(a) Determine the maximum possible efficiency of the engine.
Answer: 72.3 %
Formula:
e = 1 - (Tc / Th) = 1 - (Qc / Qh) = ( W / Qh)
Explanation: Unsure??
(b) The engine absorbs 1.15 105 J from the hot reservoir every second. If the actual efficiency of the engine is 40.3%, determine the mechanical power the engine delivers.
Answer: 46 kW
Explanation:
Energy absorbed by the engine (J) * actual efficiency of the engine (%) = mechanical power the engine delivers (kW)
How does 1 - (385/2100) = 72.3 % ?
What do I Plug in to make e = 72.3 %
Use kelvin not celsius
C + 273 = K
This will fix my problem of the equation not making sense.
What is the half-life for the radioactive decay of particle that
starts with 400.00 g and ends up with 12.50 g if the total time
was 50 minutes for the decay to occur?
Answer:
ytyug
Explanation:
4. symbol for the gravitational force ?
Answer: G
Explanation:
5. How are electromagnetic waves similar to ocean waves?.
Answer:
Electromagnetic waves have crests and troughs similar to those of ocean waves. The distance between crests is the wavelength. The shortest wavelengths are just fractions of the size of an atom, while the longest wavelengths scientists currently study can be larger than the diameter of our planet!
Explanation:
hope it's helps u ...........!
A toy car travels down a sloping ramp at constant speed. toy car Which statement about
the forces acting on the car is correct?
A There are no forces acting on the car vertically.
B There is no resultant force acting on the car.
C There is no gravitational force acting on the car.
D There is no frictional force acting on the car.
Answer:
D There is no frictional force acting on the car.
Explanation:
There isnt any friction acting on the car while its going down.
Which is larger, the sun's pull on earth or earth's pull on the sun?.
Answer:
the suns pull
Explanation:
The Sun's pull on Earth is twice as large as Earth's pull on the much larger Sun.
what causes us to perceive objects in three dimensions?
a. objects in 3-D appear to have width and height, but no depth
b. light bouncing or reflecting off an object in different ways
c. The curvature of space-time relative to objects solar mass
d. The rate of time dilation as we approach objects
Answer:
Light bouncing or reflecting off an object in different ways.
I just took a quiz and this was the answer
(k12 answer)
Light bouncing or reflecting off an object in different ways causes us to perceive objects in three-dimensions. Thus, the correct option is B.
How do we perceive objects in three dimension?Binocular fusion permits the perception of a single clear image and it also provides extra cues for the depth perception. That is, the binocular disparity between the two images is used by the nervous system of an individual to allow the perception of a three-dimensional world where the approximate distance of an object can be determined.
The depth perception is the ability to perceive the distance to objects using the visual system and visual perception.
Therefore, the correct option is B.
Learn more about Vision here:
https://brainly.com/question/7464210
#SPJ2
Please help me on this 1 assignment im giving 25 points GOOD LUCK!
Answer:
Explanation:
im sorry if this doesn't help but i think its A
. Which of the following are forces that push upward on an indoor skydiver? Choose all that apply. *
gravity
acceleration
air resistance
lift
WILL GIVE BRAINLIST
The forces that push upward on an indoor skydiver are lift force and air resistance.
The forces that act on a skydiver moving downwards includes, gravity due to his weight, air resistance and lift force.
The downward forces on the indoor skydiver include the following;
gravity due to its weightdownward force due its accelerationThe upward force on the indoor skydiver include the following;
lift forceair resistanceThus, we can conclude that the forces that push upward on an indoor skydiver are lift force and air resistance.
Learn more here:https://brainly.com/question/8947470
PLEASE ANSWER NEED HELP!!!!!!!! PLEASE THE CORRECT ANSWER!!!!!!
Why are those with low cardiovascular fitness more prone to heart disease than those whose cardiovascular fitness is high?
A.
Exercise decreases the size of arteries, causing heart disease.
B.
Those with lower cardiovascular fitness will have weaker heart muscles.
C.
High cardiovascular fitness means that the heart rate is rarely elevated.
D.
Cardiovascular fitness is the only factor that determines the strength of the heart.
PLEASE NO LINKS OR I WILL REPORT YOU
People with low cardiovascular fitness are more prone to heart disease than those whose cardiovascular fitness is high because those with lower cardiovascular fitness will have weaker heart muscles. Thus, the correct option is B.
What is Cardiovascular fitness?Cardiovascular fitness may be defined as the accommodation of the cardiovascular system to furnish oxygenated blood to functioning muscles. It includes the muscles of the heart, lungs, blood vessels, etc.
People with low cardiovascular fitness have lower furnishing of oxygenated blood to various organs like the heart, lungs, etc. Due to this, the muscles of specific body parts or organs may undergo a state of inactivity suddenly for a fraction of seconds.
This activity constantly leads to various heart-related diseases directly or indirectly in the life of an individual.
Therefore, the correct option for this question is B.
To learn more about Cardiovascular fitness, refer to the link:
https://brainly.com/question/11176067
#SPJ1
How does the electric energy between two negativly charged particles change if one particles charge is increased by a factor of 2
Answer:
i dont know this one
Explanation:
sorry i wish i could help but if u look closley on that qyestion you will understand it mor
an acorn falls from a tree. ignoring air resistance, what forces are on the acorn while it’s falling?
Answer: gravity
Explanation:
A car travels at 40 mph. what distance will it travel in 3 hours?
Car speed = 40m/ hour
3 hours = 40 × 3 = 120m /hour
Answer:
120
Explanation:
if the car travels 40 in one hour , to find the speed in 3 hours multiply 40 x 3 which will give us 120