In fraction, it would be:
-107474/10000
So a general harmonic equation is Asin(2πt/T). Little t is just a variable. 6 inches is the height of one maximum and one minimum from equilibrium, so that is the amplitude A. T is the period, or the time of one cycle (or wavelength), which is 2 seconds.
The equation is therefore (in terms of seconds and inches), 6*sin(2πt/2), or 6*sin(πt).
Yes it is rational number becauseit it s fraction
Think: To write the equation of a line in slope-intercept form y=mx+b, you must have the slope (m) and the y-intercept (b).
g(0)= -6 tells us that the y-intercept is (0, -6). Thus, b= -6.
(0,-6) and (15,-9) are points on the line. Find the slope of the line. It is:
-9-(-6)
m = ------------- = -3/15 = -1/5
15-0
Thus, the equation of the line in question is y=(-1/5)x - 6.
Important that you understand that g(0)=-6 is also represented by (0,-6), and that -6 is the y-intercept.
You figure out how long it would take a car traveling at 25 mph
to cover 360 ft. Any driver who does it in less time is speeding.
(25 mi/hr) · (5,280 ft/mile) · (1 hr / 3,600 sec)
= (25 · 5280 / 3600) ft/sec = (36 and 2/3) feet per second.
To cover 360 ft at 25 mph, it would take
360 ft / (36 and 2/3 ft/sec) = 9.82 seconds .
Anybody who covers the 360 feet in less than 9.82 seconds
is moving faster than 25 mph.
_________________________________
If you're interested, here's how to do it in the other direction:
Let's say a car covers the 360 feet in ' S ' seconds.
What's the speed of the car ?
(360 ft / S sec) · (1 mile / 5280 feet) · (3600 sec/hour)
= (360 · 3600) / (S · 5280) mile/hour
= 245.5 / S miles per hour .
The teacher timed one car crossing both strips in 7.0 seconds.
How fast was that car traveling ?
245.5 / 7.0 = 35.1 miles per hour
Another teacher timed another car that took 9.82 seconds to cross
both strips. How fast was this car traveling ?
245.5 / 9.82 = 25 miles per hour
