Let s represent the length of any one side of the original square. The longer side of the resulting rectangle is s + 9 and the shorter side s - 2.
The area of this rectangle is (s+9)(s-2) = 60 in^2.
This is a quadratic equation and can be solved using various methods. Let's rewrite this equation in standard form: s^2 + 7s - 18 = 60, or:
s^2 + 7s - 78 = 0. This factors as follows: (s+13)(s-6)=0, so that s = -13 and s= 6. Discard s = -13, since the side length cannot be negative. Then s = 6, and the area of the original square was 36 in^2.
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Answer:
<h2>
-29.61m/s</h2>
Step-by-step explanation:
Given the distance of fall of the student in term of the time t expressed by the equation s(t) = −16t² + 8√t, to get the average speed of fall of the pencil after 2.8 secs, we will need to differentiate the given function first since Velocity is the change in distance of a body with respect to time i.e
V = d(s(t))/dt
s(t) = −16t² + 8t^1/2
V = -32t+1/2(8)t^(1/2 - 1)
V = -32t+4t^-1/2
The average speed of the fall Using the fact that the pencil hit the ground in exactly 2.8 seconds, will be gotten by substituting t = 2.8 into the resulting equation.
V = -32t+4(2.8)^-1/2
V = -32t+4/√2.8
V = -32+4/1.6733
V = -32+2.391
v = -29.61m/s
<em>Hence the average speed of the fall is -29.61m/s</em>
