Total walkway length = 200 metersThe walkway moves at a constant speed of 0.5 meters per second.
[hr]
Carla:Part 1: Running for 40 seconds at 1 m/s relative to the walkwaySince the walkway is also moving at 0.5 m/s, Carla's actual ground speed is:
1 + 0.5 = 1.5 m/s
Distance covered in 40 seconds:
1.5 × 40 = 60 meters
[hr]
Part 2: She stops running for x seconds and stands stillDuring this time, she moves only with the walkway at 0.5 m/s.
Distance covered in this phase: 0.5x
Total distance so far = 60 + 0.5x
[hr]
Part 3: She resumes running at 1.5 m/s relative to the walkway for 5 secondsSo ground speed = 1.5 + 0.5 = 2 m/s
Distance = 2 × 5 = 10 meters
Now the total distance Carla covers in all three parts is:
60 (first part) + 0.5x (second part) + 10 (third part) = 200 meters
That gives us the equation:
60 + 0.5x + 10 = 200
=> 0.5x = 130
=> x = 260
So the correct value for
x is 260[hr]
Daniel:He walks from start to finish without stopping at a constant rate of 0.5 m/s
relative to the walkway.
So his actual ground speed = 0.5 + 0.5 = 1 m/s
To travel 200 meters at 1 m/s, time = 200 / 1 = 200 seconds
So the correct value for
y is 200[hr]
Final Answers:x = 260
y = 200
Bunuel
In a certain mega-shopping mall, Carla and Daniel start from the beginning of a 200-meter-long moving walkway and move in the same direction as the walkway, which travels at a constant speed of 0.5 meters per second.
- Carla starts running at a constant rate of 1 meter per second relative to the walkway, continues running for exactly 40 seconds, and then stops running for x seconds. While not running, Carla stands still and is carried only by the walkway.
- Afterward, she resumes running at 1.5 meters per second relative to the walkway for exactly 5 seconds, at which point she reaches the end of the walkway.
- Daniel walks at a constant rate of 0.5 meter per second relative to the walkway, from start to finish without stopping, and reaches the end in y seconds.
Select for
x and
y the value of of x and y, that are consistent with the information provided. Make only two selections, one in each column.