Answer:

Explanation:
<u>Average Speed
</u>
If an object travels a distance d in a time t regardless of the direction, the average speed is the quotient of the distance over the time:

It's known a person runs d=15 kilometers in t=2 hours, thus his/her average speed is:

Calculating:

Answer:
Approximately
(assuming that the projectile was launched at angle of
above the horizon.)
Explanation:
Initial vertical component of velocity:
.
The question assumed that there is no drag on this projectile. Additionally, the altitude of this projectile just before landing
is the same as the altitude
at which this projectile was launched:
.
Hence, the initial vertical velocity of this projectile would be the exact opposite of the vertical velocity of this projectile right before landing. Since the initial vertical velocity is
(upwards,) the vertical velocity right before landing would be
(downwards.) The change in vertical velocity is:
.
Since there is no drag on this projectile, the vertical acceleration of this projectile would be
. In other words,
.
Hence, the time it takes to achieve a (vertical) velocity change of
would be:
.
Hence, this projectile would be in the air for approximately
.
Density is varying through the world’s oceans. The density of ocean water is not uniform.
Question 1's answer is, if we change the length of the string allowed to vibrate, then the frequency (and pitch) of the string vibration will change. This is because the tension of the string determines the pitch.
Question 2's answer is 2. This can be solved by doing simple division. 30/15 = 2.
Question 3's answer is short bars. Each bar on a xylophone produces a different pitch; the shorter the bar, the higher the pitch.
Hope this helps.
Answer:
D
Explanation:
Weight and force have same derived units