Net force and acceleration

  • Thread starter Sko
  • Start date
  • #1
Sko
I'm doing some problems I found here:

http://library.thinkquest.org/10796/ch4/ch4q.htm

A car is moving at a constant velocity of 20 km/h (5.56 m/s). How much net force is required to raise its velocity to 50 km/h (13.89 m/s) in 30 seconds? Suppose the car has a mass of 150 kg.

I used F= (150kg)([13.89m/s-5.56m/s]/30s)
and got 41.65 N but apparently that's wrong. What am I doing wrong?
 
Last edited by a moderator:

Answers and Replies

  • #2
Doc Al
Mentor
45,178
1,498
The only thing you're doing wrong is writing your answer with too many significant digits. :smile: Round off to two digits.
 
  • #3
Sko
Ha! My phsycis teacher doesn't make us use significant figures (chem teacher did last year) so I completely forgot to do that :P
 

Related Threads on Net force and acceleration

  • Last Post
Replies
7
Views
656
Replies
3
Views
8K
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
1
Views
6K
Replies
6
Views
450
Replies
5
Views
679
  • Last Post
Replies
1
Views
2K
Replies
1
Views
2K
Replies
1
Views
3K
Replies
28
Views
2K
Top