soal nomor 29 oleh Michelle XL/29

Tentukanlah :
a. Percepatan benda pada berbagai selang waktu,
b. Perpindahan benda antara t = 0 sampai t = 20s, dan
c. Perpindahan benda antara t = 20 sampai t = 80s.
Jawab :
a. a 1 = ∆v/∆t
= 15-0 / 20-0
= 15 / 20
= 3 / 4
a 2 = 0
a3 = 0-15 / 80-60
= -15 / 20
= -3 / 4
b. S1 = V0 x t + ½ x a x t2
= 0 x 20 + ½ x ¾ x 202
= 0 + 3/8 x 400
= 150
c. S2 = V x t
= 15 x 40
= 600
S3 = V0 x t + ½ x a x t2
= 15 x 20 + ½ (-3/4) 202
= 300 – 3/8 x 400
= 300 – 150
= 150
S2 + s3 = 600 + 150 = 750