- OKAY. WE'RE NOW DOING MODULE 2, HOMEWORK PROBLEM 2.
AND THE PROBLEM READS:
CONVERT EACH OF THE FOLLOWING TO THREE SIGNIFICANT FIGURES.
WE HAVE "A" 20-POUND FEET TO NEWTON METERS,
B WOULD BE 450 POUNDS PER CUBIC FOOT
TO KILONEWTONS PER CUBIC METER
AND C 15 FEET PER HOUR TO MILLIMETERS PER SECOND.
OKAY, SO PART "A,"
WE START OFF WITH 20-FOOT POUNDS.
WE'RE GOING TO MULTIPLY BY ONES AGAIN,
SO WE HAVE 4.448 NEWTON EQUAL TO DENOMINATORS A POUND.
AND WE ALSO NOW MULTIPLY BY ONE, WE HAVE 0.3048 METERS PER FOOT.
SO GRINDING ALL OF THAT OUT, WE'RE GOING TO END UP WITH--
POUNDS GET CANCELED OUT, FEET GET CANCELED OUT,
AND WE END UP WITH 27.1 NEWTON METERS.
PART B, WE HAVE OUR 450 POUNDS PER CUBIC FOOT TIMES 1,
WHICH IS 4.448 NEWTONS, IS EQUAL TO 1 POUND.
SO POUNDS WILL CANCEL TIMES 1.
AGAIN, WE KNOW THAT 1 KILONEWTON IS EQUAL TO THE DENOMINATOR--
WOULD BE 1,000 NEWTONS.
SO THE NEWTONS HERE CANCEL OUT AND TIMES 1 AGAIN,
WHICH 1 CUBIC FOOT IS EQUAL TO 0.3048 CUBED, METERS CUBED.
GRIND THAT OUT ON THE CALCULATOR,
WE END UP WITH 70.7 KILONEWTONS PER CUBIC METER.
PART C, WE HAVE 15 FEET PER HOUR,
MULTIPLY BY 1 AGAIN, WHICH WE KNOW
THERE'S 304.8 MILLIMETERS EQUALS 1 FOOT,
MULTIPLIED BY 1.
AGAIN, WE KNOW THAT 1 HOUR IS EQUAL TO 3,600 SECONDS.
OKAY, OUR FEET CANCEL, HOURS CANCEL,
AND WE END UP WITH 1.27 MILLIMETERS PER SECOND. �