answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
timama [110]
2 years ago
9

A farmer uses 3450 J of energy on a wheel and axle to lift a 15 kg bucket of water 20 m to the top of her well. What is the effi

ciency of the system?
Physics
2 answers:
Anika [276]2 years ago
8 0

<span>Efficiency is the measure of how efficient a process is. It is used to assess the ability of a process in avoiding waste energy, materials, money and time in doing a desirable output. It is calculated as;

Efficiency = useful energy ouput / total energy input</span>

<span>Efficiency = 15(9.81)(20) / 3450 = 0.85</span>

faltersainse [42]2 years ago
5 0

Output= m*g*h = 15*9.8*20 = 2,940J


Input= 3450J (given)


Efficiency = output/input = 2,940/3450 = 0.85% efficient



You might be interested in
If no friction acts on a diver during a dive, then which of the following statements is true? A) The total mechanical energy of
EleoNora [17]
If no frictional work is considered, then the energy of the system (the driver at all positions is conserved.

Let
position 1 = initial height of the diver (h₁), together with the initial velocity (v₁).
position 2 = final height of the diver (h₂) and the final velocity (v₂).

The initial PE = mgh₁ and the initial KE  = (1/2)mv₁²
where g = acceleration due to gravity,
m = mass of the diver.
Similarly, the final PE and KE are respectively mgh₂ and (1/2)mv₂².
PE in position 1 is converted into KE due to the loss in height from position 1 to position 2.
 
Therefore
(KE + PE) ₁ = (KE + PE)₂

Evaluate the given answers.
A) The total mechanical energy of the system increases.
     FALSE

B) Potential energy can be converted into kinetic energy but not vice versa.
     TRUE

C) (KE + PE)beginning = (KE + PE) end.
     TRUE

D) All of the above.
     FALSE

4 0
2 years ago
Read 2 more answers
A CCD has a greatest possible pixel value of 4095. what is the bit level of this CCD?
Shtirlitz [24]
<span>Bit level for a CCD (Charged coupled device) with a greatest possible pixel value of 4095:The relationship between the bit level and pixel value is given as:pixel value = 2^bit level.Most charged coupled devices (CCDs) have 8-bit, 16-bit, 32-bit levels.Using simple mathematics, we can see that 2^12 = 4096.Since the maximum number of pixels is 4095, the bit level is 12., i.e. the CCD has 12-bit level.</span>
8 0
2 years ago
The acceleration of the car with two washers added to the string would be what?
sleet_krkn [62]

Answer: The answer is 0.33

Explanation: got the question right :)

7 0
2 years ago
Read 2 more answers
16. A 7500 kg 18-wheeler traveling at 20 m/s exits onto the runaway truck ramp on the freeway.
miskamm [114]

Answer:

<em>765,000 Joule</em>

Explanation:

<u>Principle of Conservation of Energy </u>

The total energy in an isolated system cannot be created or destroyed, but transformed. Moving objects have kinetic energy, objects placed in some height above a reference level have gravitational potential energy. When they change their motion variables, one energy converts into the other, but if the numbers don't fit, we know there was some other type of energy acting into the system. The most common reason for energy 'losses' is the thermal energy, produced when objects move in rough surfaces or take friction from the air.

The 7,500 kg truck is originally traveling at 20 m/s to a certain height we'll set to 0. Thus, its total energy is  

\displaystyle E_1=\frac{mv^2}{2}

\displaystyle E_1=\frac{7,500\ 20^2}{2}

E_1=1,500,000\ Joule

When it comes to a stop, its speed is 0 and its height is 10 m higher than before. It means all the kinetic energy was transformed into other types of energy. The gravitational potential energy is

U=mgh=(7,500)(9.8)(10)=735,000\ Joule

Since this number is not equal to the previous value of the energy, the difference is due to thermal energy dissipated by friction

E_t=1,500,000\ Joule-735,000\ Joule=765,000\ Joule

7 0
2 years ago
One end of a string is fixed. An object attached to the other end moves on a horizontal plane with uniform circular motion of ra
sveticcg [70]

Answer:

If both the radius and frequency are doubled, then the tension is increased 8 times.

Explanation:

The radial acceleration (a_{r}), measured in meters per square second, experimented by the moving end of the string is determined by the following kinematic formula:

a_{r} = 4\pi^{2}\cdot f^{2}\cdot R (1)

Where:

f - Frequency, measured in hertz.

R - Radius of rotation, measured in meters.

From Second Newton's Law, the centripetal acceleration is due to the existence of tension (T), measured in newtons, through the string, then we derive the following model:

\Sigma F = T = m\cdot a_{r} (2)

Where m is the mass of the object, measured in kilograms.

By applying (1) in (2), we have the following formula:

T = 4\pi^{2}\cdot m\cdot f^{2}\cdot R (3)

From where we conclude that tension is directly proportional to the radius and the square of frequency. Then, if radius and frequency are doubled, then the ratio between tensions is:

\frac{T_{2}}{T_{1}} = \left(\frac{f_{2}}{f_{1}} \right)^{2}\cdot \left(\frac{R_{2}}{R_{1}} \right) (4)

\frac{T_{2}}{T_{1}} = 4\cdot 2

\frac{T_{2}}{T_{1}} = 8

If both the radius and frequency are doubled, then the tension is increased 8 times.

5 0
2 years ago
Other questions:
  • A Labrador retriever breeder needs to determine if three male pups who were born to Sadie, his black Labrador retriever, are the
    11·1 answer
  • A 1.0 kg brick falls off a ledge of height 44m and lands on the ground at 3.0 s later.
    6·1 answer
  • A roller coaster travels 200 feet horizontally and then rises 135 feet at an angle of 30 degrees above the ground. What is the m
    7·1 answer
  • Five metal samples, with equal masses, are heated to 200oC. Each solid is dropped into a beaker containing 200 ml 15oC water. Wh
    5·1 answer
  • When an ice pack is applied to an injury, thermal energy from the injured area transfers to the ice, causing the blood vessels w
    8·2 answers
  • A box rests on the (horizontal) back of a truck. The coefficient of static friction between the box and the surface on which it
    10·1 answer
  • Biologists have studied the running ability of the northern quoll, a marsupial indigenous to Australia. In one set of experiment
    14·2 answers
  • What's the diameter of a dish antenna that will receive 10−20W of power from Voyager at this time? Assume that the radio transmi
    14·1 answer
  • A binary star system consists of two stars of masses m1 and m2. The stars, which gravitationally attract each other, revolve aro
    12·1 answer
  • While dangling a hairdryer by its cord, you observe that the cord is vertical when the hairdryer isoff and, once it is turned on
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!