Pick any value of x <-2 or greater than 7 and you will get a positive result (greater than zero) for the equation.
Remember F = ma (this is the equation StarStrike used)
F/a = m
784.8/9.81 = 80 kg
Yah, I saw that and corrected my mis-interp before you told me that....sorry....
Never mind....my mistake...... your answer looks good..
Wise Old Owl says : "Three"
They do not need MULTIPLE gears like a gasoline/deisel powered car. The have torque available all all motor RPMs and have but a single SPEED REDUCTION gear in the drivetrain. (Much like some airplanes have for the propeller so it spins at a lower speed than the direct engine RPM.... PSRU Propeller Speed Reduction Unit)
As a ratio
6 1/3 / (8 1/2) = x / (4 1/4)
4 1/4 * 6 1/3 /(8 1/2) = 3 1/6 ft redwood
It is a sin wave with origin 0
it is shifted UP by 2
sin x + 2
8t^2 <= 3-10t
8t^2 + 10t - 3 <=0 Quadratic formula results in zeroes at 1/4 and - 3/2
this is an UPWARD opening parabola, so the values less than zero are between these two zeroes [-3/2,1/4]
Think about getting a cube of clay and molding it into a ball....the ball will be taller.
Cube volume = h x h x h 10 in ^3 = h^3 h = 2.15 inches tall
Sphere volume = 4/3 pi r^3 = 10 results in r = 1.33 Diameter = 2r = 2.67 inches tall