Help with this physics problem

  • Thread starter Janzen
  • Start date
  • #1
1
0
Hey just starting physics and i am lost. This is the problem:
A car traveling 35 mi/h is to stop on a 35 meter long shoulder of the road. What minimum deceleration is required?

If you could type out How you would this is would be GREATLY appreciated.

Thanks
 

Answers and Replies

  • #2
167
0
okay well 1st of all convert mi/h to km/h because the stopping area is given in metres.

The question essentially asks how rapidly must the car decelerate in order to reach a velocity of 0 over 35 metres.

Well the average speed the car will have is 1/2 its initial velocity if we take decleration to be uniform. Therefore, using 1 mi = 1.5 k, the car will have an average speed of 26.25 km/h.

This is equivalent to 437.5m/minute or 7.29166m/second.

Therefore the car will cover the 35 metres in <5seconds.

Therefore the car must decelerate at >7m/s to stop in time
 
  • #3
159
0
You might also find this formula to be very useful
[tex]v_2^2 = v_1^2 + 2ad[/tex]
 

Related Threads on Help with this physics problem

Replies
1
Views
2K
  • Last Post
Replies
4
Views
784
Replies
2
Views
3K
Replies
3
Views
1K
Replies
2
Views
3K
Replies
7
Views
1K
Replies
8
Views
3K
Replies
2
Views
126
Replies
4
Views
5K
Replies
3
Views
1K
Top