The answer would be a.
a chemical change is a change to the chemical makeup of a substance so if the bonds are unchanged it would be a characteristic of a physical change
My answer i believe is simply 250 Hz, because sounds or vibrations travel in 1 cycle/second, meaning the number of cycles, in your case 250, divided by the time,1 second, will ultimately be 250 Hertz. For every Cycle/second it will equal 1 Hz, so 250/1 = 250Hz
Answer;
D. rocket engines are not dependent on oxygen from the air.
Explanation;
-Jet engines and rockets work on the same principle. They produce thrust through an internal pressure difference and, as explained by Newton’s Third Law of Motion, eject exhaust gases in an equal and opposite direction.
-The main difference between them is that jets get the oxygen to burn fuel from the air and rockets carry their own oxygen, which allows them to operate in space.
Additionally, Jet engines have two openings (an intake and an exhaust nozzle). Rocket engines only have one opening (an exhaust nozzle).
Venus would be an inner planet!
x
Answer:
U² = 142.86 N
U¹ = 357.14 N
Explanation:
Taking summation of the moment about point A, we get the following equilibrium equation: (taking clockwise direction as positive)
where,
W = weight of boy = 500 N
U² = reaction ay B = ?
Therefore,
<u>U² = 142.86 N</u>
Now, taking summation of forces on the plank. Taking upward direction as positive, for equilibrium position:
<u>U¹ = 357.14 N</u>
