- #1

Imperil

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QUESTION:

A bird takes 8.5 s to fly from position A (va= 4.4 m/s (31 ° S of E) to position B(vb= 7.8 m/s ( 25° N of E) along the path. Find the bird's average acceleration.

MY ANSWER

vax/va = cos31

vax = 3.8 m/s

vay/va = sin31

vay = -2.3 m/s

vbx/vb = cos25

vbx = 7.1 m/s

vby/vb = sin32

vby = 3.3 m/s

ax = vbx - vax / t

ax = 7.1 m/s - 3.8 m/s / 8.5s

ax = 0.4 m/s(2)

ay = vby - vbx / t

ay = 3.3 m/s + 2.3 m/s / 8.5s

ay = 0.7 m/s(2)

a(2) = ax(2) + ay(2)

a(2) = 0.16 + 0.49

a = 0.8 m/s(2)

tan(theta) = ay / ax

tan(theta) = 0.7 m/s(2) / 0.4 m/s(2)

tan(theta) = 1.75

theta = 60 degrees

Therefore the bird's acerage acceleration is 0.8 m/s 60 degrees N of E.