Answer:
5. All of the statements are true; non is false
Explanation:
Answer:
The forces that do non-zero work on the block are gravity and normal reaction force
Explanation:
C., used in power plants I think.
Answer: F = 20 N
Explanation:
I will ASSUME that the fulcrum is at the center of gravity of the lever arm, This means that the lever arm itself creates no moment about the fulcrum because there is no moment arm for that particular force.
To solve, we sum moments about any convenient point to zero (zero because there is no acceleration in the F = ma equation)
The easiest convenient point is the fulcrum
30((90/2) - 15) - F(90/2) = 0
30(30) = F(45)
F = 900/45 = 20 N
The same bird on the tree has more gravitational potential energy. This is because it is at a higher distance from the ground as it is on the tree, than when it is on the ground.
Considering also the formula for Gravitational Potential Energy GPE = mgh
For the bird on the ground, h =0, therefore GPE = m*9.8*0 = 0
For that on the tree = mgh = m*9.8*h
Of course the one on the tree has a value greater than zero.
