Go Back   Physics Help Forum > High School and Pre-University Physics Help > Kinematics and Dynamics

Kinematics and Dynamics Kinematics and Dynamics Physics Help Forum

Reply
 
LinkBack Thread Tools Display Modes
Old Sep 7th 2010, 07:44 PM   #1
Junior Member
 
Join Date: Sep 2010
Posts: 9
motion along a line

Hello,

I'm working on this problem:

Select all the correct answers. A particle moving along a straight line is increasing its speed if
  • its velocity v is positive.
  • its acceleration a is positive
  • Both a>0 and v>0.
  • Both a<0 and v<0.
I know that an object is speeding up if and only if v and a point in the same direction. So, I think the answer would be the last two, e.g.,

  • Both a>0 and v>0.
  • Both a<0 and v<0.
Is this correct?
centenial is offline   Reply With Quote
Old Sep 8th 2010, 09:35 AM   #2
Physics Team
 
ChipB's Avatar
 
Join Date: Jun 2010
Location: Morristown, NJ USA
Posts: 2,347
Yes, you are correct. However the question is poorly worderd - I assume that what they meant to as is: "A particle moving along a straight line must be increasing its speed if ..." Certainly answers a and b could apply to a particle that is increasing its speed, but they may also apply to particles that are decreasing their speed as well.
ChipB is offline   Reply With Quote
Reply

  Physics Help Forum > High School and Pre-University Physics Help > Kinematics and Dynamics

Tags
line, motion



Thread Tools
Display Modes


Similar Physics Forum Discussions
Thread Thread Starter Forum Replies Last Post
The line formula philipishin Philosophy of Physics 2 Sep 27th 2016 11:32 PM
straight line motion Mounir Kinematics and Dynamics 2 Mar 23rd 2010 06:48 AM
Question regarding Dynamics 1:Motion Along a Line Solid8Snake Kinematics and Dynamics 3 Oct 8th 2009 08:40 AM
straight line motion mattc Kinematics and Dynamics 6 Sep 9th 2009 08:29 PM
Velocity-time line/Acceleration-time line graph. ariol Kinematics and Dynamics 1 Jan 8th 2009 10:08 PM


Facebook Twitter Google+ RSS Feed