A subway train starts from rest at a station and accelerates at a rate of 1.60 m/s}^{2} for 14.0 s. It runs at constant speed for 70.0 s and slows down at a rate of 3.50 m}/s}^{2} until it stops at the next station. Find the total distance covered.
2006-09-22 17:28:59 · 6 answers · asked by darkangelwattitude 1 in Science & Mathematics ➔ Physics
Acceleration phase:
s=1/2 at^2
s=1/2 * 1.6 *14^2 = 156.8 m
At that point, the train moves at v=at = 1.6 * 14=22.4 m/s, so for 70 seconds, the distance traveled at constant speed is 22.4 * 70 = 1568 m/
Deceleration phase:
v=a t
22.4 = 3.5 * t so t is 6.4 seconds
Distance travelled during deceleration is
s=1/2 a t^2 = 71.68 m
total distance travelled is thus 1796.48 m
2006-09-22 17:36:12 · answer #1 · answered by Vincent G 7 · 1⤊ 0⤋
Since it accelerates at a rate of 1.6 for 14 seconds, it reaches a speed of 22.4 m/s. At that rate in 70 seconds it travels 1568 meters. Then it takes 6.4 seconds to stop. All you need to figure out now is how far it travels while accelerating and slowing down!
2006-09-23 00:47:59 · answer #2 · answered by DadOnline 6 · 0⤊ 0⤋
acceleration part,
S=ut+0.5at^2
=0.5(1.60)(14)^2
=156.8m
constant speed part,
speed=1.60x14.0
=22.4m/s
distance=22.4x70.0
=1568m
deceleration part,
v^2=u^2+2aS
0=22.4^2+2(-3.50)S
S=71.68m
total distance=156.8+1568+71.68
=1796.48m
2006-09-23 00:38:20 · answer #3 · answered by Thomas Green 1 · 1⤊ 0⤋
Dude, you are not having physics problems. You are having math problems. It's meters per second per second, give the total number of meters. Do your homework and count the meters
2006-09-23 00:36:41 · answer #4 · answered by Anonymous · 0⤊ 1⤋
First this professor must to know problem of hgh -frequency line source then,this professor must to know nonlinear phenomena inpermitivity and permitivity tensors ,electromagnetic transverse waves and more many others
2006-09-23 00:35:48 · answer #5 · answered by www. o 1 · 0⤊ 3⤋
1.6 m/s^ *14s = 22.4m/s
2006-09-23 00:39:27 · answer #6 · answered by alandicho 5 · 0⤊ 0⤋