PLEASE HELP - basic SUVAT stuff
A,B and C are 3 points lying in that order on a straight line with AB =60 metres and AC = 80 metres. A body moves from A to B at an average speed of 10 metres per second then from B to C in a time of 4 seconds and then returns to B. The average speed for the whole journey is 5 metres per second.

Find:
1. the average speed of the body during the second stage of motion from B to C.
2. the average speed of the body in moving from A to C
3. the time taken for the 3rd stage of motion from C back to B
4. the average velocity for the complete motion

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MathPhys MathPhys · Answer 1 · 2019-08-02T16:23:15+02:00

Answer:

1. 5 m/s

2. 8 m/s

3. 10 s

4. 3 m/s

Explanation:

1. Average speed = distance / time

s = 20 m / 4 s

s = 5 m/s

2. First, find the time to travel from A to B:

60 m = 10 m/s × t

t = 6 s

Now find the average speed from A to C:

s = 80 m / (6 s + 4 s)

s = 8 m/s

3. If t is the time traveling from C back to B, and the average speed of the whole trip is 5 m/s, then:

5 m/s = 100 m / (6 s + 4 s + t)

t = 10 s

4. Average velocity = displacement / time

v = 60 m / 20 s

v = 3 m/s