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kiruha [24]
3 years ago
10

Steve does 80 J of work to a rope threaded through a pulley and attached to a crate of anvils. The tension of the rope is 10 N a

nd the crate rises 4 m while Steve pulls. What is the efficiency of the pulley? [Hint: how much work was done on the crate?]
a) (A) 0.07 or 7 %
b) (B) 0.2 or 20 %
c) (C) 0.5 or 50 %
d) (D) 1 or 100 %
Physics
2 answers:
Ivahew [28]3 years ago
6 0

Answer:

The Answer is (B)

Explanation:

zimovet [89]3 years ago
5 0
The answer would be letter b
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Missing graph. I attach it in the answer.

In a uniformly accelerated motion, the velocity at time t is given by:
v(t)=at
where a is the acceleration and t is the time.

Given the previous equation, if we plot v(t) versus t, we find a straight line; moreover, a (the acceleration) represents the slope of the curve.

Looking at the graph, we see that when the time goes from 10 s to 20 s, the velocity increases from 4 m/s to 6 m/s. Therefore the slope of the curve is
a= \frac{\Delta v}{\Delta t}= \frac{6 m/s-4 m/s}{20 s-10 s}= \frac{2 m/s}{10 s}=0.2 m/s^2
and this corresponds to the acceleration.

So, the correct answer is <span>0.2 m/s2.</span>

7 0
4 years ago
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Where would a boat produce the highest concentration of carbon monoxide?
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<span>A boat would produce the highest concentration of carbon monoxide in the exhaust system.

</span>Carbon monoxide<span> (CO) is a colorless, odorless, and tasteless gas that is slightly less dense than air. It is toxic to </span>hemoglobic<span> <span>animals (both </span></span>invertebrate<span> <span>and vertebrate, including humans) when encountered in concentrations above about 35 </span></span>ppm<span>.</span>

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3 years ago
Describe the frequency and wavelength range of radio waves
sammy [17]

Answer:

Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. They have frequencies from 300 GHz to as low as 3 kHz, and corresponding wavelengths from 1 millimeter to 100 kilometers.

Explanation:

3 0
3 years ago
two ice skaters push each other, and move in opposite directions. the mass of one is 75 kg, and his speed is 2 m/s. if the mass
sattari [20]

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4 years ago
A moving car skids to a stop with the wheels locked across a level roadway. Of the forces listed, identify which act on the car.
Vesnalui [34]

Answer:

Normal, Gravity, Friction, and Air Resistance.

Explanation:

When a moving car skid to stop and its wheels are locked across, then the following forces will be applied on the car:

<u>Normal force:</u> It will act counter to gravity that pushes an object against a surface and acts perpendicular to the contact surface.

<u>Gravity:</u> Gravity force acts in each and every object having mass and it can not be avoidable. So, the gravity force will also apply to the car and attract it to the earth's surface.

<u>Friction: </u>Friction is a force that acts opposite to the motion and stops or slows motion. Friction will be applied to the car that will oppose the motion of the car and stop it.

<u>Air resistance:</u> air resistance is defined as the forces exerted by air that acts opposite to the relative motion of an object. Air resistance will also be applied to the car when it will skid to stop as we are always surrounded by the air.

Hence, the correct answers are "Normal, Gravity, Friction, and Air Resistance."

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