<span>The answer is B. It can be converted from high to low voltage and vice versa using transformers. That is why high voltages (tens or hundreds of kilovolts) is used to efficiently transfer electricity for large distances and then converted to 110-240V.
The answer can also be derived by elimination. [A] is not right because battery provides only Direct Current (DC). [C] is not right because high voltages are used for AC (from 110V to hundreds of kilovolts). [D] is not right because as the name Alternating Current suggests, the current is alternating in its direction. [E] is not right because DC was the first type of current invented.</span>
The properties of acids are: (A), (C) and (D).
Explanation:
Acids taste sour, and most
acids are poisonous. Furthermore, acids react with certain metals to
produce hydrogen gas. Few acids are corrosive as well. The option (B) is not valid because acids react with BASES (not with other acids) to produce salt and water. Hence A, C and D are the correct options.
We are given a box that slides up a ramp. To determine the force of friction we will use the following relationship:
Where.
To determine the Normal force we will add the forces in the direction perpendicular to the ramp, we will call this direction the y-direction as shown in the following diagram:
In the diagram we have:
Adding the forces in the y-direction we get:
Since there is no movement in the y-direction the sum of forces must be equal to zero:
Now we solve for the normal force:
To determine the y-component of the weight we will use the trigonometric function cosine:
Now we multiply both sides by "mg":
Now we substitute this value in the expression for the normal force:
Now we substitute this in the expression for the friction force:
Now we substitute the given values:
Solving the operations:
Therefore, the force of friction is 15.01 Newtons.
Answer:
Explanation:
Since energy is conserved:
2
mu
2
=
2
mv
2
+mgh
⇒u
2
=v
2
+2gh
⇒(3)
2
=v
2
+2(9.8)(0.5−0.5cos60)
⇒v=2m/s
