Answer:
The girl is doing work on the ball because the energy in her muscles changed, even though the ball is not displaced.
Explanation:
The complete question is...
Which of these correctly describes whether a girl holding a ball in the same position is doing work on the ball?
-The girl is doing work on the ball because the energy of the ball changed, even though it is not displaced.
-The girl is doing work on the ball because the energy in her muscles changed, even though the ball is not displaced.
-The girl is doing no work on the ball because the ball is not displaced.
-The girl is doing no work on the ball because she is exerting a net force on the ball.
Holding up a ball costs energy, which is used to counter the work that would have otherwise be done on the ball by gravity. Although no physical distance is moved, we should consider the fact that by holding the ball, the girls hand exerts physical force to hold the ball in place. Also, there is a potential gravitational work on the ball due to gravity, but the force exerted by the girls hand does an equivalent of this gravito-potential work in order to counter it and hold the ball in place. All these activities eventually lead to a change in energy in her hand muscle to show that energy is expended.
A - opposite
I have to write 20 characters so....jghghgyf
The answer is F=3.906 x 10^-9
1. Encoding Information
2. Storing Information
3. Retrieval Information
Answer:
The correct option is;
B. 8 m, because he has to apply less force over a greater distance
Explanation:
In the given question, in order for the student to lift the boxes onto the tuck with less amount of force, he applies the principle of Mechanical Advantage
The mechanical advantage is given by the measure by which a force is amplified through the use of a tool
Given that the work done = The force × The distance, we have
F₁ × d₁ = F₂ × d₂, which gives;
d₁/d₂ = F₂/F₁
Where;
F₁ = The input force
F₂ = The output force
d₁ = The input distance
d₂ = The output distance
The Mechanical advantage, MA = d₁/d₂ = F₂/F₁
Therefore, when the input distance is increased the input force will be reduced for a given output force