13 A cyclist is travelling along a straight horizontal road. As she passes a bus
ID: 1660455 • Letter: 1
Question
13 A cyclist is travelling along a straight horizontal road. As she passes a bus stop she sces a red traffic light ahead of her. She continues to travel with a constant speed of 3 m st for 20 seconds and then decelerates at a constant rate of 0.2 m s2 until coming to rest at the traffic light. (a) Calculate the distance between the bus stop and the traffic light. Calculate the time the cyclist takes to travel from the bus stop to the traffic light. Calculate the average speed of the cyclist between the bus stop and the traffic light. (b) (c) EA]Explanation / Answer
(a)
When she had a constant speed, she travelled 20 * 3 = 60 m
When she was decelerating:
u = 3
a = -0.2
v = 0
v^2 - u^2 = 2ad
0^2 - 3^2 = 2*(-0.2)*d
0 - 9 = -0.4d
-9 = -0.4d
d = (-9) / (-0.4)
d = 22.5
Total distance: 60 + 22.5 = 82.5m
(b)
When she was decelerating:
u = 3
a = -0.2
v = 0
v = u + at
0 = 3 - 0.2t
0.2t = 3
t = 3 / 0.2
t = 15
Total time: 20 + 15 = 35s
(c) 82.5 / 35 = 33 / 14 =~ 2.36 m/s
Related Questions
Hire Me For All Your Tutoring Needs
Integrity-first tutoring: clear explanations, guidance, and feedback.
Drop an Email at
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.