Answer:
Efficiency = 71%
Explanation:
Given the following data:
Output energy = 250 Joules
Input energy = 350 Joules
To find efficiency;
Substituting into the equation, we have;

Efficiency = 71.43 ≈ 71%
Therefore, the efficiency of the candle is 71 percent.
Answer:
The velocity is 19.39 m/s
Solution:
As per the question:
Mass, m = 75 kg
Radius, R = 19.2 m
Now,
When the mass is at the top position in the loop, then the necessary centrifugal force is to keep the mass on the path is provided by the gravitational force acting downwards.


where
v = velocity
g = acceleration due to gravity

The answer would be to research the need. This should have been done before the project began.
Explanation:
The given data is as follows.
mass (m) = 170 kg, Distance (s) = 9.6 m
Height (h) = 3.3 m, Force (F) = 1400 N
First, we will calculate the work performed by her as follows.
W = Fs
= 
= 13440 J
Hence, minimal work necessary to lift the refrigerator is as follows.
U = mgh
= 
= 5497.8 J
Therefore, we can conclude that he performed 5497.8 J of work.
The density of sample is 5 g/cm3
Given:
volume of sample = 20 cm3
mass of sample = 100 grams
To Find:
density of sample
Solution: Density is the measure of how much “stuff” is in a given amount of space. For example, a block of the heavier element lead (Pb) will be denser than the softer, lighter element gold (Au). A block of Styrofoam is less dense than a brick. It is defined as mass per unit volume
density = mass/volume
d = 100/20
d = 5 g/cm3
So, density of sample is 5 g/cm3
Learn more about Density here:
brainly.com/question/1354972
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