1answer.
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
Firdavs [7]
3 years ago
7

A refrigerator with a weight of 1,127 newtons needs to be moved into a house using a ramp. The length of the ramp is 2.1 meters,

and its height is 0.85 meters. What is the percentage efficiency if a force of 496 newtons is applied to the refrigerator?
Physics
2 answers:
Levart [38]3 years ago
4 0

Answer:

91.9 %

Explanation:

The percentage efficiency is equal to the ratio between the output work and the input work:

\eta = \frac{W_{out}}{W_{in}} \cdot 100

The output work is equal to the gravitational potential energy gained by the refrigerator, which is equal to its weight (W=1,127 N) times the gain in height (h=0.85 m):

W_{out}=Wh=(1127 N)(0.85 m)=958 J

The input work is equal to the product between the force applied on the refrigerator (F=496 N) and the displacement of the refrigerator (d=2.1 m):

W_{in}=Fd=(496 N)(2.1 m)=1042 J

So, the efficiency is

\eta=\frac{958 J}{1042 J}\cdot 100=91.9 \%

mestny [16]3 years ago
3 0
The used work of energy output is 496*2.1=1041.6 J. And the actual work of energy output is 1127*0.85=957.95 J. The percentage efficiency is 957.95/1041.6*100%=91.97 %.
You might be interested in
The patellar tendon attaches to the tibia at a 20 deg angle 3 cm from the axis of rotation at the knee. If the force generated i
gregori [183]

Answer:

the resulting angular acceleration is 15.65 rad/s²

Explanation:

Given the data in the question;

force generated in the patellar tendon F = 400 N

patellar tendon attaches to the tibia at a 20° angle 3 cm( 0.03 m ) from the axis of rotation at the knee.

so Torque produced by the knee will be;

T = F × d⊥

T = 400 N × 0.03 m × sin( 20° )

T = 400 N × 0.03 m × 0.342

T = 4.104 N.m

Now, we determine the moment of inertia of the knee

I = mk²

given that; the lower leg and foot have a combined mass of 4.2kg and a given radius of gyration of 25 cm ( 0.25 m )

we substitute

I = 4.2 kg × ( 0.25 m )²

I = 4.2 kg × 0.0626 m²

I = 0.2625 kg.m²

So from the relation of Moment of inertia, Torque and angular acceleration;

T = I∝

we make angular acceleration ∝, subject of the formula

∝ = T / I

we substitute

∝ = 4.104 / 0.2625

∝ = 15.65 rad/s²

Therefore, the resulting angular acceleration is 15.65 rad/s²

8 0
3 years ago
A ship, carrying freshwater to a desert island in the caribbean, has a horizontal cross-sectional area of 2800 m2 at the waterli
Alex17521 [72]
<span>Due that we already know the horizontal cross-sectional area of the ship, which is 2800 m2 and we are going to understand that value keeps constant for the whole 9.5 of height of the ship from the waterline till the new waterline after unloading, then we just need to calculate the volume as follows: V = A * H , where V is volume, A is area and H is height V= 2,800 * 9.5 = 26,600 m3 So this volum of 26,600 cubic meters is the volum of freshwater delivered in the island.</span>
3 0
3 years ago
A certain car can accelerate from 0 to 60 mph in 7.9 s. What is the car's average acceleration in mph/s?
Anna007 [38]

Answer:

<em>a = 7.6\ mph/s</em>

Explanation:

<u>Motion With Constant Acceleration </u>

It's a type of motion in which the velocity of an object changes uniformly in time.

The equation that describes the change of velocities is:

v_f=v_o+at

Where:

a   = acceleration

vo = initial speed

vf  = final speed

t    = time

Solving the equation [for a:

\displaystyle a=\frac{v_f-v_o}{t}

The car accelerates from vo=0 to vf=60 mph in t=7.9 s, thus the acceleration is:

\displaystyle a=\frac{60 \ mph-0}{7.9}

a = 7.6\ mph/s

7 0
3 years ago
What happens to a satellite that slows down?
Bess [88]

Two things can happen to <u>old satellites</u>: For the closer satellites, engineers will use its last bit of fuel to slow it down so it will fall out of orbit and burn up in the atmosphere. Further satellites are instead sent even farther away from Earth.

4 0
3 years ago
Read 2 more answers
A car starts from rest and travels for t1 seconds with a uniform acceleration a1. The driver then applies the brakes, causing a
mestny [16]
The answer for this question is b because it says how far it goes before he begins to take brake
5 0
2 years ago
Other questions:
  • Despite the gases, dust, and stars that compose the universe, it is still mostly made up of ____________________.
    5·1 answer
  • A piano string having a mass per unit length equal to 4.80 ✕ 10−3 kg/m is under a tension of 1,300 N. Find the speed with which
    10·1 answer
  • 9<br>How can you prove that air has weight​
    12·2 answers
  • What are cells? what is the relationship between cells and organisms?​
    6·2 answers
  • Galaxy B moves away from galaxy A at 0.577 times the speed of light. Galaxy C moves away from galaxy B in the same direction at
    9·1 answer
  • URGENT!!!!!!!<br><br> PLEASE HELP WITH THIS PHYSICS PROBLEM
    13·1 answer
  • Differentiate between angular displacement and linear displacement.​
    10·1 answer
  • A battery-powered lawn mower has a mass of 48.0 kg. If the net external force on
    11·1 answer
  • How are cactus adapted to survive in deserts?
    11·1 answer
  • The innermost satellite of jupiter orbits the planet with a radius of 422 × 103 km and a period of 1.77 days. what is the mass o
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!