Physics Help Forum Velocity vs time graph and questions

 Kinematics and Dynamics Kinematics and Dynamics Physics Help Forum

 Nov 18th 2008, 05:19 PM #1 Junior Member   Join Date: Nov 2008 Posts: 1 Velocity vs time graph and questions Question Details: The graph shows the change in the velocity of an object with time in a situation in which momentum is conserved. which of the following situations is most likely indicated by the graph. explain why or why not the situations is or is not the best choice.. Hint: think about conservation of linear momentum and conservation of energy to solve the problem. A) The velocity of a bullet striking a ballistic pendulum B) The velocity of a car colliding head on with another car of equal weight and velocity C) The velocity of a fixed stationary object being hit by a bullet D) The velocity of a swinging pendulum E) A ball rolling across a level floor
 Nov 18th 2008, 05:35 PM #2 Junior Member   Join Date: Nov 2008 Posts: 2 id say choice d
 Nov 18th 2008, 06:06 PM #3 Senior Member     Join Date: Apr 2008 Posts: 815 No, it's not d) because in that case the velocity changes of sign each half period. Also its velocity is never constant. I'd say A) because the velocity of the bullet would remain constant until hitting the ballistic pendulum. When it hits it the velocity would go down but not equal to $\displaystyle \frac{0m}{s}$ (as shown in the graph) because it would encrust into the pendulum and follow it's path at a lower speed according to the conservation of linear momentum. However I dislike the graph because he hasn't any scale-time reference so we must find out if the time is short (less than $\displaystyle 1 s$) or long (more than $\displaystyle 1s$). It's not B) because the car would remain quiet after the collision (means that velocity is worth $\displaystyle \frac{0m}{s}$). Nor C) because its velocity would increase (starting from $\displaystyle \frac{0m}{s}$). And I don't know about the E) because I don't know what a level floor is. __________________ Isaac If the problem is too hard just let the Universe solve it.

 Tags graph, questions, time, velocity

 Thread Tools Display Modes Linear Mode

 Similar Physics Forum Discussions Thread Thread Starter Forum Replies Last Post purplec16 Kinematics and Dynamics 2 Mar 29th 2011 07:05 PM davie08 Kinematics and Dynamics 1 Feb 27th 2011 08:18 PM alessandro Kinematics and Dynamics 1 Jan 31st 2010 08:38 AM s3a Kinematics and Dynamics 5 Mar 22nd 2009 11:01 PM ariol Kinematics and Dynamics 1 Jan 8th 2009 10:08 PM