Answer:
B. a piece of paper being torn
Explanation:
A chemical change is one that cannot be reversed. This means the original properties of the substance or object cannot be restored.
If you cook a raw egg, it would turn into a boiled egg (or a poached egg, however it is being cooked). The reaction is irreversible, so you cannot turn the cooked egg back into a raw egg - it is basically impossible to 'uncook' an already cooked egg.
When you toast a piece of bread, it turns into toast. You can't 'untoast' it back into bread. The chemical changes have already occurred and cannot be undone.
If you tear a piece of paper, it is still paper. You are only ripping it, not changing anything about it. You could simply tape the torn bit back to the original bit, or glue it - either way, it is still paper and nothing has occurred to drastically change the physical state of it.
Therefore, B is not a chemical change.
Answer:
Mantle and core
Explanation:
The Mantle and Core are the two components within Earth experiencing convection. In several ways the mantle is significant. The one outcome of convective current is the creation of the fresh oceanic lithosphere around OCEANIC RIDGES, formed by mantle upwelling. Core is indeed the planet's innermost layer.
First box and third box !
Answer:
Explanation:
There is electric field between the plates whose value is given by the following expression
electric field E = V /d where V is potential between the plates and d is distance between them
E = 300 / 5 x 10⁻³
= 60 x 10³ N/c
Force on electron = q E where q is charge on the electron
F = 1.6 X 10⁻¹⁹ X 60 X 10³ = 96 X 10⁻¹⁶ N.
Acceleration a = force / mass
a = 96 x 10⁻¹⁶/ mass = 96 x 10⁻¹⁶ / 9.1 x 10⁻³¹
= 10.55 x 10¹⁵ m / s²
For midway , distance travelled
s = 2.5 x 10⁻³ m
s = 1\2 a t²
t = 
= 
t = .474 x 10⁻¹⁸ s
For striking the plate time is calculated as follows
t = ![[tex]\sqrt{\frac{2\times5\times10^{-3}}{ 10.55\times10^{15}}](https://tex.z-dn.net/?f=%5Btex%5D%5Csqrt%7B%5Cfrac%7B2%5Ctimes5%5Ctimes10%5E%7B-3%7D%7D%7B%2010.55%5Ctimes10%5E%7B15%7D%7D)
[/tex]
t = 0.67 x 10⁻¹⁸ s
Explanation:
a) Balloon is being thrown down and is speeding up;
mg > 
b) Balloon is in the air on its way down and moving with constant speed.
=mg
c) The Balloon is on the ground and rest instantaneously
mg = Normal
d) Balloon is moving slowly downward;
e) Because, at the peak of trajectory drag force is 0.
Drag force = 0
