Picking up a sheet of paper . . . work done with small force
Picking up a glass of water . . . work done with moderate force
Picking up a huge boulder . . . work done with a great tremendous force
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Standing still . . .
Holding your tongue out as far as it will go . . .
Holding your arm over your head for 3 days . . .
Holding a huge boulder motionless over your head . . .
Pushing on a brick wall . . .
Pushing as hard as you can against a truck with the wheels locked . . .
. . . . . No work done at all, because the force doesn't move through a distance.
<u>Work done = (force) times (distance)</u>
If the force doesn't move, then the distance is zero, and the work done is zero.
When the clouds get really heavy due to increased water vapor in the air so the lower the clouds get the more likely precipitation will occur.
Answer:
Explanation:
Let assume that direction is positive when football travels to the player. The situation can be described properly by applying the definition of Momentum and Impulse Theorem. That is to say:
The average force needed to stop is obtained after some algebraic manipulations:
The impulse delivered to the ball is:
The lightning rod would most likely channel all the energy into itself instead of distributing it to the rest of the entire building
Answer:
b. 20%
Explanation:
Efficiency of an engine is a ratio in percentage of the work done to the energy intake of the engine.
η=(Q₁-Q₂)/Q₁×100%
η is efficiency, Q₁ is the energy intake, Q₂ is energy wasted.
The information provided is:
Energy intake = 400 J
Work done = 80 J = (400-320) =Q₁-Q₂
Energy wasted =320 J
η= 80/400×100%
=20%
