Answer:
The actual work output is 1,125 kilojoules.
Explanation:
Energy efficiency is defined as the efficient use of energy. An appliance, process, or facility is energy efficient when it consumes less than the average amount of energy to perform an activity. Then, energy efficiency is the ratio between the amount of energy used in an activity and the amount expected to be carried out.
Efficiency is calculated as:
efficiency = output / input
Where output is the amount of mechanical work (in watts) or energy consumed by the process (in joules), and input (input) is the amount of work or energy that is used as input to carry out the process.
In this case:
- Efficiency always has a value between 0 and 1. In this case, efficiency=0.15
- output=?
- input= 7500 kilojoules
Replacing:
0.15=output/7500 kilojoules
Solving:
Output=0.15* 7500 kilojoules
output=1,125 kilojoules
<u><em>The actual work output is 1,125 kilojoules.</em></u>
Answer:
Same
Explanation:
Let R be the resistance of the cell and E be the emf.
Let i be the current in the circuit.
i = E / R ..... (1)
Now emf and resistance be doubled.
so, i' = 2E/2R = E/R
So, i' = i (From equation (1)
Current remains same.
Answer:
Mass.
Explanation:
I took the quiz and got the answer right
a) 
, 
The work done by the student in each trial is equal to the gravitational potential energy gained by the student:
where
m = 68 kg is the mass of the student
g = 9.8 m/s^2 is the acceleration of gravity
is the gain in height of the student
For the first student, 
, so the work done is
The second student runs up to the same height (3.5 m), so the work done by the second student is the same:
2) 
, 
The power exerted by each student is given by
where
W is the work done
t is the time taken
For the first student, and 
, so the power exerted is
For the second student, 
and 
, so the power exerted is
