Answer:
vDP = 21.7454 m/s
θ = 200.3693°
Explanation:
Given
vDE = 7.5 m/s
vPE = 20.2 m/s
Required: vDP
Assume that
vDE to be in direction of - j
vPE to be in direction of i
According to relative motion concept the velocity vDP is given by
vDP = vDE - vPE (I)
Substitute in (I) to get that
vDP = - 7.5 j - 20.2 i
The magnitude of vDP is given by
vDP = √((- 7.5)²+(- 20.2)²) m/s = 21.7454 m/s
θ = Arctan (- 7.5/- 20.2) = 20.3693°
θ is in 3rd quadrant so add 180°
θ = 20.3693° + 180° = 200.3693°
Answer:
A. velocity has a direction .. .
with magnitude too but speed has only magnitude
The car has a 12 mile head start, going 80 mph, so his distance is:dcar=80∗t+12
The is going at 108 mph, so his distance is:dcop=108t
Setting them equal to each other we get:80t+12=108t⇒12=28t⇒t=1228=37
So 3/7 of an hour.about 25.7 mins.
