A record of travel along a straight path is as follows: 1. Start from rest with
ID: 1528810 • Letter: A
Question
A record of travel along a straight path is as follows:
1. Start from rest with a constant acceleration of 2.40 m/s2 for 20.0 s.
2. Maintain a constant velocity for the next 3.00 min.
3. Apply a constant negative acceleration of 9.30 m/s2 for 5.16 s.
(a) What was the total displacement for the trip?
m
(b) What were the average speeds for legs 1, 2, and 3 of the trip, as well as for the complete trip?
Explanation / Answer
a) total displacement, d = d1 + d2 + d3
= (vo*t1 + (1/2)*a1*t1^2) + (v*t2) + (v*t3 + (1/2)*a2*t3^2)
= (0 + (1/2)*2.4*20^2) + (20*2.4*3*60) + (2.4*20*5.16 - (1/2)*9.3*5.16^2)
= 480 + 8640 + 124
= 9244 m
b)
leg1, v_avg1 = d1/t1
= 480/20
= 24 m/s
leg2, v_avg2 = d2/t2
= 8640/(3*60)
= 48 m/s
leg3, v_avg3 = d3/t3
= 124/(5.16)
= 24 m/s