We are given a watermelon dropped at free fall from a building 320 meters above the sidewalk. Superman is headed down at 30 meters per second. We are asked to determine how fast is the watermelon going when it passes Superman. To solve for the final velocity of the watermelon, we will use one of the kinematic equations (free fall):

vf = vi + a*t

where vf is the final velocity
vi is the initial velocity, zero
a is the acceleration, in this case, gravitational acceleration = 9.8m/s^2
t is time

we also need to set-up another equation using the distance:

d = vf + vi / 2 * t

(1) 320 m = vf * t /2

(2) vf = 9.8 m/s^2 * t

From here, we have two equations and two unknown, thus we can solve the problem by substitution.

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8 0

3 years ago

I know that real numbers consist of the natural or counting numbers, whole numbers, integers, rational numbers and irrational nu

ra1l [238]

The imaginary unit $i$ belongs to the set of complex numbers, denoted by $\mathbb C$ . These numbers take the form $a+bi$ , where $a,b$ are any real numbers.

The set of real numbers, $\mathbb R$ , is a subset of $\mathbb C$ , where each number in $\mathbb R$ can be obtained by taking $b=0$ and letting $a$ be any real number.

But any number in $\mathbb C$ with non-zero imaginary part is not a real number. This includes $i$ .

"is it possible that i can use an imaginary number for a real number"

I'm not sure what you mean by this part of your question. It is possible to represent any real number as a complex number, but not a purely imaginary one. All real numbers are complex, but not all complex numbers are real. For example, 2 is real and complex because $2=2+0i$ .

There are some operations that you can carry out on purely imaginary numbers to get a purely real number. A famous example is raising $i$ to the $i$ -th power. Since $i=e^{i\pi/2}$ , we have

$i^i=\left(e^{i\pi/2}\right)^i=e^{i^2\pi/2}=e^{-\pi/2}\approx0.2079$

3 0

2 years ago