Answer:
B. After a photon of light is absorbed by certain metals, electrons are found to be ejected from the metals. This is because the energy contained in the massless photon is used to eject an electron with mass out of the metal.
Explanation:
Before, in the early days, it was proposed to form a combined theory by joining the theory of conservation of mass and the theory of conservation of energy and form a combined theory of conservation of mass-energy. It was done to explain a particular theory of 
.
The is the emission of the electrons form the surface of a metal when light energy strikes on it. Here, in this phenomenon, both mass and energy is conserved.
When the light strikes a metal surface, electrons gets ejected from the surface. The energy of the photon is used to eject the electron form the metal surface.
The value of the final speed depends on the mass of the ore.
Let's call m the mass of the ore. We can solve the exercise by requiring the conservation of momentum, which must be the same before and after the ore is loaded.
Initially, there is only the cart, so the momentum is
After the ore is loaded, the new mass will be (1200 kg+m), and the new speed is
. The momentum p is conserved, so it is still 12960 kg m/s. Therefore, we have
and so the final speed is
2: It's not just the capillary action, but the pull from transpiration (the evaporation of water from the tree) that is used to pull water up from the roots.
<span>The second question needs context. Strong bonds alone won't cause tension. I don't see how adhesion is different. High vapour pressure could do it, but it's the difference in pressures that'd cause tension (and the resistance of that pressure by the surface). So, a low and high pressure would be needed. Poorly worded question :( </span>
<span>1: "Adhesion is the tendency of certain dissimilar molecules to cling together due to attractive forces." [1] </span>
<span>3: The other three answere would not work. Think of a boat. </span>
<span>3: If you push gas, it will be compressed(get smaller). If you push liquid it will push something else. Thus, liquids are good for transferring force. This is a hydraulic system.</span>
Answer:
The work done by the frictional force is 600J.
Explanation:
The work 
done by the frictional force is
.
Now, 
and 
; therefore,
Hence, the work done by friction is 660J.
