Question

1-D catch-up: Two cars move with constant velocities. At t = 0, a blue car is at xBo = 20 m. After t = 4s in the blue car time frame of reference, a red car located then at xRo = 0m, within 3 seconds catches up with the blue car at xB = XR = 60 m.
Find the velocities of blue and red cars.

Answer 1

Answer:

5.71 m/s ;

20 m/s

Explanation:

Blue car:

At time, t = 0 ; Initial position = 20 m

Final position, = 60m after 4 seconds

The velocity = change in distance / change in time.

Velocity of blue = (60 - 20)m ÷ ((4 + 3) - 0),

Velocity of blue car = 40 / 7

= 5.71 m/s

Red car:

Initial Position = 0 ; final Position = 60

Time taken = 3 seconds

Velocity of Red car = (60 - 0)m ÷ 3

Velocity of Red car = 60 / 3

= 20 m/s