What is the % efficiency of this system ?

In summary, the conversation covers three physics problems, including a question about a fish collision, a pulley system, and an inelastic collision between two objects. The larger fish's velocity after lunch is -4 m/s, the man puts in 200 watts of power and gets out 150 watts, and the efficiency of the pulley system is 75%. The question about energy dissipation in the collision is answered with a hint to use the principle of conservation of energy. The person also requests help but states that the rules are not to do their homework for them.
  • #1
PhysicsNoob88
24
0
These are some problems I am having difficulty with, the first problem I got an answer but I am unsure if it is correct and the others I have no clue. If you can step by step how to do them it would be greatly appericated.

A 12 kg. fish swimming at a velocity of 3 m/s swallows an absent-minded 4 kg fish swimming toward it at 10 m/s. What is the velocity, including direction (e.g., direction of larger fish or smaller fish), of the larger fish after lunch ?

I used m=mv and I got the answer to be -4m/s (big fish travels bacwards from its original postion) < I am not sure if this is correct if you can verify that would be awsome.

2) A pulley system is set up to lift boxes weighing 750 N from ground level to a position 6 meters high. A man pulls 30 meters of rope with a force of 200 N.

(b) If it takes the man 50 seconds to accomplish this task, (1) how much power is he putting in and (2) how much power is he getting out ?



(c) What is the % efficiency of this system ?



3) Consider the inelastic collision between two objects (A and B). Object A has a mass of 10 kg. and is moving at 12 m/s. Object B has a mass of 6 kg. and is moving at 8 m/s toward object A (Objects A and B are moving towards each other). How much energy is dissipated as heat ?

HINT: The velocity of the wreckage must first be determined. Then use the principle of conservation of energy.

To whom who ever does it I truly thank you. :redface:
 
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  • #2
I need the answers by 10 minutes from now, please anyone help...
 
  • #3
For number two, [itex]P = \frac{W}{t}[/itex] and [itex]W= Fd[/itex]. Can you go from here?
 
  • #4
PhysicsNoob88 said:
I need the answers by 10 minutes from now, please anyone help...

the rules are that we don't do your homework for you.
 
  • #5
For No. 1 first conserve momentum and then v = momentum/mass
 
  • #6
For no.3
whether the collision is elastic or inelastic momentum is conserved.
The difference of initial and final energies is the heat dissipated.
 

What is the % efficiency of this system?

The % efficiency of a system is a measure of how well a system converts input energy into useful output energy. It is usually represented as a percentage and can range from 0% (no output energy) to 100% (all input energy converted into useful output energy).

How is % efficiency calculated?

The % efficiency of a system is calculated by dividing the useful output energy by the total input energy and then multiplying by 100. The formula is: % efficiency = (useful output energy / total input energy) * 100.

What factors can affect % efficiency?

The % efficiency of a system can be affected by various factors such as the design and quality of the system, external factors like temperature and humidity, and the type of energy being converted. Inefficient processes and energy losses can also impact the % efficiency of a system.

How does % efficiency differ from energy conversion efficiency?

% efficiency and energy conversion efficiency are related concepts but have different meanings. % efficiency is a measure of how well a system converts input energy into useful output energy, while energy conversion efficiency is a measure of how well a system converts one form of energy into another (e.g. electrical energy into mechanical energy).

Why is it important to know the % efficiency of a system?

Knowing the % efficiency of a system is important for understanding how well it is performing and identifying areas for improvement. It can also help in making informed decisions about the use of energy resources and promoting sustainable practices.

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