## Friday, May 23, 2014

### PCalc and HP 50G: Escape Velocity

The next four posts will have programs for the PCalc iOS app and the HP 50g calculator. English/U.S. Units (feet/miles, pounds, seconds) will be used instead of SI units (meters/kilometers, kilograms, seconds).

The Universal Gravitational Constant is:

SI Units:
G = 6.67384 x 10^-11 m^3/(s^2 kg)

English Units:
G = 1.06904661604 x 10^-9 ft^3/(s^2 lb)

PCalc Program: Escape Velocity (in mi/sec)
5/19/2014

G = 1.06904661604 x 10^-9 ft^3/(s^2 lb)

Input:
Y: mass (in pounds)
X: distance or radius (in miles)

Output:
Y: mass (in pounds)
X: escape velocity (mi/sec)

Program:
Decimal Mode
Multiply X By 5280
Invert X
Multiply X By Y
Multiply X By 2
Multiply X By 1.0690441604e-9
X To Power of 0.5
Divide X By 5280

Example:
Y: 1.3170e25 lbs (Mass of Earth)
X: 3,959 mi (radius of Earth)

Output:
Y: 1.3170e25
X: 6.9512

Escape Velocity: 6.9512 mi/sec

HP 50g: Escape Velocity:

Input:
2: mass in pounds
1: distance in miles

Output:
1: escape velocity in mi/sec

Program ESCVEL
<< 5280 * INV * 2 * 1.0690441604E-9 * √ 5280 / >>

This blog is property of Edward Shore. 2014