Answer:
the aluminum would have the most mass
First find the time it takes to hit the sand t
using s=1/2 g t^2
t^2= 8/9.8= 0.82 seconds
This means the sand was s = 8 * 0.82 = 6.5m away
The horizontal speed stays constant at 8 m/s
The vertical speed =.82 * 9.8 = 8.0 m/s
As the two velocities are equal the angle must be 45 degrees to the horizontal
Suppose rowing speed is V km/s.
So, upstream speed = V-2
Downstream speed = V+ 2
Total time is taken 3 h 20 min to cover up and down journey of 5 km.
So, total time = upstream time + downstream time
and 
, we take only positive velocity.
Thus, the the rowing speed of the crew in still water is 1 km/s.
Answer:
The light radiated from the Sun's surface reaches Earth in about 8 minutes. However, the energy of this light was released by fusion in the Sun's core about several hundred thousand years ago.
Explanation:
Nucleosynthesis is the fusion of lighter elements into heavier elements. For the Sun the main mechanism of fusion is the proton - proton chain, in which two hydrogen atoms fuse into helium, in the course of the fusion photons are created.
When those photons start their travel from the core to the surface of the star, they will interact with different atoms in the whole way (the main free path).
More precisely, when a photon¹ is absorbed by an electron in an atom of a particular element, the electron will get to a higher state. When it comes back to the ground state, a photon will be emitted again.
The process described above is repeating multiple times for every photon until they reach the Sun surface.
The whole process can take about several hundred thousand of years.
Key term:
¹Photon: Particle that constitutes light.
