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:
high, low
Explanation:
- Energy always flows from a higher level to a lower level.
- It is analogous to the waterfall where waterfalls from a higher level to a lower level.
- So in the case of the pressure of the gas, when there are any numbers of molecules in a given volume of space. The gas is said to be at high pressure.
- When there are fewer molecules in the given volume. The gas is said to be at lower pressure.
- Due to a large number of atoms, the high-pressure gas exerts more force on the container than the force exerted by the low-pressure gas.
- If a hose is connected between these two containers, gas rushes from high pressure to the low pressure. Since the force exerted by the high-pressure gas is greater than that of low-pressure gas.
So, the wind tends to move from high-pressure areas to low pressure.
Answer:
Work done W =1406.25 J
Explanation:
Work done on a body can be calculated using newton's 2nd laws:
F=ma
Hence acceleration of the block is given by:
Displacement of the object is given by:
Substitute the values
Now work done is given by:
W=F.S
W = 25×56.25
W =1406.25 J
Answer:
A
Explanation:
because the speed divide by the frequency is equal to the wavelength(in meters)
5×10² m
C. Magnetic draws certain types of metal together.
