It would be kinetic energy. Let's say the book is weighs 10 Newtons you need to use a force of 10 Newtons to lift the book. In other words it's positive. As you move the book you're giving it energy. Namely potential energy which will turn to kinetic energy if you let it go. So you're changing it's position and energy.
I found this on google
<span>There are three main types of pulleys: fixed, movable, and compound. A fixed pulley's wheel and axle stay in one place. A good example of a fixed pulley is a flag pole: When you pull down on the rope, the direction of force is redirected by the pulley, and you raise the flag.</span>
The answer to this question is option 2
<u>Answer:</u>
The force F applied to the handle = 330.03 N
<u>Explanation:</u>
The force can be resolved in to two, horizontal component and vertical component. If θ is the angle between horizontal and applied force we have
Horizontal component of force = F cos θ
Vertical component of force = F sin θ
In this problem normal force exerted on the suitcase is 160 N, that is vertical component of force = 160 N and angle θ = 29⁰.
So, F sin 29 = 160
F = 330.03 N
The force F applied to the handle = 330.03 N
Answer:a) 492 nm; b) 1.78 eV
Explanation: In order to solve this problem we have to use the photoelectric energy balance givenb by:
h*ν=Ek+W where h is the Placnk constant, ν is the frequency of the radiation, Ek is the kinetic energy of the realised electrons and W is the work funcion of the incident metal.
Then we have:
W=h*ν-Ek= h*c/λ-Ek=1240 eV.nm/176 nm=2.52 eV
so the maximun wavelength to realese the electrons is when Ek=0 then
W=h*c/λmax so λmax= h*c/W= 1240/2.52=492.06 nm
Finally if we use 288 nm to realease the electrons, then Ek of the emitted electron from the metal is:
from h*ν=Ek+W we have:
Ek=h*c/λ-W= (1240/288) eV*nm-2.52 eV=1.78 eV