Newton’s Third Law of Motion states that for every action there is an equal and opposite reaction. So look for a scenario in which something had force applied upon it and the reaction is a force in the opposite direction of the same size.
Answer:
Ro = 8.65 [g/cm³]
Explanation:
We must remember that density is defined as the ratio of mass to volume.
where:
m = mass = 0.450 [kg] = 450 [g]
V = volumen = 52 [cm³]
Ro = density [g/cm³]
Now replacing:
![Ro = 450/52\\Ro = 8.65 [g/cm^{3} ]](https://tex.z-dn.net/?f=Ro%20%3D%20450%2F52%5C%5CRo%20%3D%208.65%20%5Bg%2Fcm%5E%7B3%7D%20%5D)
M = 30 g = 0.03 kg, the mass of the bullet
v = 500 m/s, the velocity of the bullet
By definition, the KE (kinetic energy) of the bullet is
KE = (1/2)*m*v²
= 0.5*(0.03 kg)*(500 m/s)² = 3750 J
Because the bullet comes to rest, the change in mechanical energy is 3750 J.
The work done by the wall to stop the bullet in 12 cm is
W = (1/2)*(F N)*(0.12 m) = 0.06F J
If energy losses in the form of heat or sound waves are ignored, then
W = KE.
That is,
0.06F = 3750
F = 62500 N = 62.5 kN
Answer:
(a) 3750 J
(b) 62.5 kN
That's what stars do all the time.
For example, in the sun (and MOST other stars), deep down in the center
of the sun's core, two atoms of Hydrogen get squashed together so hard
that they blend into one atom of Helium AND release some energy.
That's where the sun's energy all comes from. It's called "nuclear fusion".
It needs tremendous temperature and pressure to happen. We know how
to do it, but we can't control it. So far, the only thing we've ever been able
to use it for is Hydrogen bombs.
There are 92 elements on the Periodic Table that are found in nature,
plus another 20 or so that have been made in the laboratory, but only
a few atoms of them.
