Answer:
VAB = 20km/hr
Explanation:
<u>Given the following data;</u>
Velocity of car A, VA = 60km/hr
Velocity of car B, VB = 80km/hr
To find the relative velocity of B w.r.t A, VAB;
Since the two cars are moving in the same direction, we have;
VAB = VB - VA
Substituting into the equation, we have;
VAB = 80 - 60
<em>VAB = 20km/hr</em>
Therefore, the relative velocity of car B with respect to car A is 20 kilometers per hour.
I don't think that 4m has anything to do with the problem.
anyway. here.
A___________________B_______C
where A is the point that the train was released.
B is where the wheel started to stick
C is where it stopped
From A to B, v=2.5m/s, it takes 2s to go A to B so t=2
AB= v*t = 2.5 * 2 = 5m
The train comes to a stop 7.7 m from the point at which it was released so AC=7.7m
then BC= AC-AB = 7.7-5 = 2.7m
now consider BC
v^2=u^2+2as
where u is initial speed, in this case is 2.5m/s
v is final speed, train stop at C so final speed=0, so v=0
a is acceleration
s is displacement, which is BC=2.7m
substitute all the number into equation, we have
0^2 = 2.5^2 + 2*a*2.7
0 = 6.25 + 5.4a
a = -6.25/5.4 = -1.157
so acceleration is -1.157m/(s^2)
