Ideal mechanical advantage doesn't take energy lost to friction into account. Explain why the mechanical advantage of a single fixed pulley is always 1. A single fixed pulley changes only the direction of the effort force. ... Energy transforms from the object supplying the force to the object being moved.
Your body is pushing down on a chair because it is being attracted by gravity, the reason that your body is not moving down because there is a normal force acting on your body; together the net force of weight (m*g) and normal force is equal to zero
The correct answer is B. 24 N.
To figure out the exact force the cart exerts on the woman, we have to use Newton's third law of motion. Newton's third law of motion states that every action has an equal and opposite reaction. This means that if object 1 exerts a force on object 2 , object 2 will exert an equal but opposite force on object 1.
This law allows us to ignore the masses of the chart and the women and focus on the pairs of forces the woman and the chart apply to each other. Since the woman exerts a force of 24 N on the chart, the chart will exert a force of 24 N on the woman.
The correct answer is B. 24 N.
Answer:
The change in the charge on the positve plate when the Teflon is inserted is +2.5 nC.
Explanation:
- It can be showed that the capacitance of a parallel-plate capacitor, can be expresssed as follows:

- Where ε, is the dielectric constant of the material that fills the space between plates.
- When this space is filled with air, ε= ε₀ = 8,85*10⁻¹² F/m.
- At the same time, the capacitance of a capacitor, by definition, is as follows:

- If we insert a Teflon slab, in such a way that fills completely the gap between the plates, all other parameters being equal, if ε = 2*ε₀, this means that C₂ = 2* C₁. = 50 pF
- As V₂=V₁ (due to the capacitor remains connected to the same battery) the charge must be the double, so Q₂ = 2* Q₁ = 5 nC.
- So, the change in the charge of the positive plate is +2.5 nC.
Answer:652.05 J
Explanation:
Given
Weight of lifter 
vertical distance move 
Work done in lifting the weight is equal change in Potential Energy of weight
Change in Potential Energy 

therefore work done is equal to