vf=vi+at
a=-0.08 m/s²
vi=1 m/s
t=4 s
Calculate the average velocity for a remote controlled vehicle that starts with a speed of 1.0 m/s [forward] and then accelerates at
0.08 m/s2 [backward] for 4.0 s.
2 answers
Let forward be +, backward be -
vi = +1.0 m/s
a = -0.08 m/s²
t = 4.0 s
Δd = ?
d = vi(t)+1/2(a)(t²)
d = (1.0)(4.0)+1/2(-0.08)(4.0²)
Δd = 3.36 m
Now, using the definition of average velocity [which is *not* (vi+vf)/2]:
v_avg = Δd/Δt
v_avg = 3.36/4.0
v_avg = 0.84 m/s
vi = +1.0 m/s
a = -0.08 m/s²
t = 4.0 s
Δd = ?
d = vi(t)+1/2(a)(t²)
d = (1.0)(4.0)+1/2(-0.08)(4.0²)
Δd = 3.36 m
Now, using the definition of average velocity [which is *not* (vi+vf)/2]:
v_avg = Δd/Δt
v_avg = 3.36/4.0
v_avg = 0.84 m/s