It takes Serina 0.25 hours to drive to school. Her route is 21 km long. What is Serina’s average speed on her drive to school?
1 answer:
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The time taken by traveler to cover the distance is,
Substitute the known values,
Therefore, the time taken by traveler to cover the distance is 89.3 s.
<h2>Answer: 10.52m</h2><h2 />
First, we have to establish the <u>reference system</u>. Let's assume that the building is on the negative y-axis and that the brick was thrown at the origin (see figure attached).
According to this, the initial velocity has two components, because the brick was thrown at an angle
:
(1)
(2)
(3)
(4)
As this is a projectile motion, we have two principal equations related:
<h2>In the x-axis: </h2> (5)
Where:
is the distance where the brick landed
is the time in seconds
If we already know and
, we have to find the time (we will need it for the following equation):
(6)
(7)
(8)
Where:
is the height of the building (<u>in this case it has a negative sign because of the reference system we chose)</u>
is the acceleration due gravity
Substituting the known values, including the time we found on equation (7) in equation (8), we will find the height of the building:
(9)
(10)
Multiplying by -1 each side of the equation:
>>>>This is the height of the building