Answer: His acceleration is -18.66m/s^2
Explanation:
Ok, the initial speed is 2.8m/s. (we can define the initial direction as the positive direction).
And he wants to stop, so he must accelerate in the opposite direction as the initial movement, then we would have:
a(t) = -A.
So we have a constant, and negative acceleration.
Now, if we want to find the velocity we must integrate over time, and we will get:
v(t) = -A*t + V0
where V0 is the initial velocity, we know that it is 2.8m/s, and t is the time in seconds.
Then the velocity is:
v(t) = -A*t + 2.8m/s.
Now we know that John is brought to rest in 0.15 seconds after he starts slowing down, this means that at t = 0.15 seconds, his velocity is equal to zero.
v(0.15s) = 0m/s = -A*0.15s + 2.8m/s
2.8m/s = A*0.15s
2.8m/s/0.15s = 18.66m/s^2 = A.
So his acceleration is -A, then we have that:
His acceleration is -18.66m/s^2
Kinetic energy = (mv^2)/2. So (.5)(10^2)/2 = 25 J
Answer:
Volcanic lightning is created when a volcano erupts and lots of tiny fine particles of volcanic ash form a cloud. Friction between the particles of ash and the gases emitted from the eruption cause differentces that create lightning. Friction between the particles of ash and the gases emitted from the eruption cause differentces that create lightning. The lightning usually occurs between clouds and from the eruption column to the crater.
Explanation:
please mark brainliest if this helped :)
Answer:
As ice melts into water, kinetic energy is being added to the particles. This causes them to be 'excited' and they break the bonds that hold them together as a solid, resulting in a change of state: solid -> liquid.
Explanation:
As we may know, the change in state of an object is due to the change in the average kinetic energy of the particles.
This average kinetic energy is proportional to the temperature of the particles.
This is because heat is a form of energy; by adding energy to ice - heat, you "excite" the water molecules, breaking the interactions in the lattice structure and forming weaker, looser hydrogen-bonding interactions.
This causes the ice to melt. This is demonstrated in the image below.
More generally, when you remove energy - the object cools down, the particles move a lot slower. So slow, that they individually attract other molecules more than before, and this results in a physical change that also changes the state.
Answer:
D
Explanation:
The atomic number of hydrogen is 1, because hydrogen is considered the number #1 element in the periodic table. Hope this helps!