Answer:
Efficiency is the percent of work put into a machine by the user (input work) that becomes work done by the machine (output work).
Explanation:
It is a measure of how well a machine reduces friction.
The greatest variation in size, mass, and luminosity occurs in elliptical galaxies.
<h3>What is Variation?</h3>
This is defined as the difference from the norm which is exhibited by objects.
In the solar system, variation in features such as size, mass, and luminosity occurs mostly in elliptical galaxies due to presence of array of stars thereby making it the most appropriate choice.
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The acceleration of the car is 0.8049
.It takes 13.802s to travel the 230 m.
<h3>
What is acceleration?</h3>
In mechanics, acceleration refers to the rate at which an object's velocity with respect to time varies. Acceleration is a vector quantity (in that they have magnitude and direction). The direction of an object's acceleration is determined by the direction of the net force acting on it. Newton's Second Law states that the combined effect of two factors determines how much an item accelerates:
(i) It follows that the magnitude of the net balance of all external forces acting on the object is directly proportional to the magnitude of this net resulting force, and
(ii) the mass of the thing, depending on the materials out of which it is constructed, is inversely proportional to the mass of the thing.
Calculations:
40 km/hr ----- 11.11m/s
80 km/hr ----- 22.22m/s

Time taken
v-u=at
22.22-11.11= 0.8049 x t
t=13.802s
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Answer:
All the physical world objects that comers in the contact to exert the force to each other. The contact forces are different from their names and what type of force they exert.
Explanation:
The cables and the ropes are the useful objects that exert the forces that can efficiently transfer the force from a significant distance.
It is noted that tension is a type of force that the rope can not simply push it away effectively. When push happened with rope, the rope goes to slack and lose all the tension that pulls at the first place. Tension only pull objects.