Kinematics question on brakes

  • #1
Hi, can someone please check if this is right?

A driver applies brakes on seeing a traffic signal 400m ahead. At the time of applying the brakes, the vehicle was moving with 15m/s and retarding with 0.3m/s^2. What is the distance of the vehicle from the traffic light after 1 minute?

x = 15(60) - 1/2(0.3)(60)^2
x = 360m

Therefore the distance from the traffic light is 40m. Correct?
My book says the answer is 25m. Is it wrong? Any help will be appreciated.Thanks!
 

Answers and Replies

  • #2
147
0
I can't see anything wrong with your work. Either the book is wrong or we're both reading the question wrong (ie: the driver starts breaking after 1 second and then breaks for a minute)
 
  • #3
1
0
Hi, can someone please check if this is right?

A driver applies brakes on seeing a traffic signal 400m ahead. At the time of applying the brakes, the vehicle was moving with 15m/s and retarding with 0.3m/s^2. What is the distance of the vehicle from the traffic light after 1 minute?

x = 15(60) - 1/2(0.3)(60)^2
x = 360m

Therefore the distance from the traffic light is 40m. Correct?
My book says the answer is 25m. Is it wrong? Any help will be appreciated.Thanks!

hey BOY,
SEE the driver has applied brakes so just calculate the time the car ll take to stop by the eq. v=u+at.Then just calc the dis by eq s=ut+1/2at^2....the dis ll be 375m.so dis from traffic light is 400-375 i.e 25 m dear.
PARAS sir
SUNITI CLASSES
for further assistance contact:09810855099
 

Related Threads on Kinematics question on brakes

Replies
1
Views
4K
  • Last Post
Replies
4
Views
3K
  • Last Post
Replies
4
Views
1K
Replies
3
Views
876
  • Last Post
Replies
7
Views
2K
  • Last Post
Replies
8
Views
1K
  • Last Post
Replies
1
Views
930
  • Last Post
Replies
7
Views
2K
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
20
Views
4K
Top