Answer: H
Explanation:
When beavers dam a stream they slow the movement of water. Behind the beaver dam, a pond of still water is formed. This pond is then colonized by animals and plants that typically live in lakes rather than streams.
Explanation:
(a) Displacement of an object is the shortest path covered by it.
In this problem, a student is biking to school. She travels 0.7 km north, then realizes something has fallen out of her bag. She travels 0.3 km south to retrieve her item. She then travels 0.4 mi north to arrive at school.
0.4 miles = 0.64 km
displacement = 0.7-0.3+0.64 = 1.04 km
(b) Average velocity = total displacement/total time
t = 15 min = 0.25 hour

Hence, this is the required solution.
The formula for velocity is distance divided by time, or d/t. The distance is 500 km and the time is 1.2 hours. 500/1.2 is 416.6 km/hr.
Answer:
A: The acceleration is 7.7 m/s up the inclined plane.
B: It will take the block 0.36 seconds to move 0.5 meters up along the inclined plane
Explanation:
Let us work with variables and set

As shown in the attached free body diagram, we choose our coordinates such that the x-axis is parallel to the inclined plane and the y-axis is perpendicular. We do this because it greatly simplifies our calculations.
Part A:
From the free body diagram we see that the total force along the x-axis is:

Now the force of friction is
where
is the normal force and from the diagram it is 
Thus
Therefore,

Substituting the value for
we get:

Now acceleration is simply

The negative sign indicates that the acceleration is directed up the incline.
Part B:

Which can be rearranged to solve for t:

Substitute the value of
and
and we get:
which is our answer.
Notice that in using the formula to calculate time we used the positive value of
, because for this formula absolute value is needed.
Answer:
<u><em>Electric Potential Energy:</em></u>
The energy that is needed to move a charge against an electric firld is called Electric Potential Energy
<u><em>Electric Potential Difference:</em></u>
The amount of work done in carrying a unit charge from one point to an other in an electric field is called Electric Potential Difference.
<u><em>Relation:</em></u>
Relation between Electric potential and electrical potential energy is given by

Here PE represents Electric potential energy
and
is Electric potential difference
it means electric potential difference is the difference in electric potential energy divided by the charge.