The time taken by the rock will be 8.77 seconds.
<h3>What is speed?</h3>
Speed is defined as the ratio of the time distance traveled by the body to the time taken by the body to cover the distance.
Given that:-
The equation for free fall at the surface of some planet (s in meters, t in seconds) is s = 2.86t²
The time will be calculated by using the speed formula.
Speed = Distance \ Time
25.1 = 2.86t² \ t
t = 25.1 / 2.86
t = 8.77 seconds
Therefore the time taken by the rock will be 8.77 seconds.
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Answer:
7.16
Step-by-step explanation:
Answer:
I dont think so I would look at it as how did they get the -2
The sketch of the parabola is attached below
We have the focus

The point

The directrix, c at

The steps to find the equation of the parabola are as follows
Step 1
Find the distance between the focus and the point P using Pythagoras. We have two coordinates;

and

.
We need the vertical and horizontal distances to find the hypotenuse (the diagram is shown in the second diagram).
The distance between the focus and point P is given by

Step 2
Find the distance between the point P to the directrix

. It is a vertical distance between y and c, expressed as

Step 3
The equation of parabola is then given as

=


⇒ substituting a, b and c


⇒Rearranging and making

the subject gives