Question
a student drops an object out the window of the top floor of a high-rise dormitory
a) neglecting air resistance, how fast is the object traveling when it strikes the ground at the end of 3.0 s? express the speed in mi/h for a familiar comparison,
b) how far, in meters, does the object fall during the 3.0 s? How many floors does the dormitory probably have?
a) neglecting air resistance, how fast is the object traveling when it strikes the ground at the end of 3.0 s? express the speed in mi/h for a familiar comparison,
b) how far, in meters, does the object fall during the 3.0 s? How many floors does the dormitory probably have?
Answers
Damon
come on now, use what we have done
v = g t
but to go from m/s to mi/hr
use
3600 seconds / hour
and 1609 meters/mile
a floor is about 3 meters
v = g t
but to go from m/s to mi/hr
use
3600 seconds / hour
and 1609 meters/mile
a floor is about 3 meters
Damon
WORK IN METRIC
convert later if dealing with carpenters.
convert later if dealing with carpenters.
Katie
is it d = 1/2 (9.8) (3)^2 = 44.1 m/s^2/3s =14.7 m/s x 2 = 32.87 = 32.87 mi/h?
and
b) d= 1/2 (9.8) (3)^2 =44.1 m/s^2/35 = 14.7 m/s
and
b) d= 1/2 (9.8) (3)^2 =44.1 m/s^2/35 = 14.7 m/s
Damon
You are terrribly fouled up with units. Give me a minute
Damon
the ground is 3 seconds down
d = (1/2) (9.81) (3)^2 correct
d = 44.1 METERS (THAT IS PART B)
(that is 9.81 m/s^2 * 9 s^2 so just m or meters)
NOW THE SPEED (Part A)
v = g t
v = 9.81 m/s^2 * 3 s = 29.4 m/s
(THAT IS PART A)
d = (1/2) (9.81) (3)^2 correct
d = 44.1 METERS (THAT IS PART B)
(that is 9.81 m/s^2 * 9 s^2 so just m or meters)
NOW THE SPEED (Part A)
v = g t
v = 9.81 m/s^2 * 3 s = 29.4 m/s
(THAT IS PART A)
Damon
BUT they want miles/ hr
so
29.4 m/s * 1 mile/1609 m * 3600 s/h
= 65.8 miles/hour
so
29.4 m/s * 1 mile/1609 m * 3600 s/h
= 65.8 miles/hour