- #1

sirfederation

- 20

- 0

This is an example from my engineering physics book which didn't have an answer at the end of the book,

This figure is a snapshot looking down on a frictionless puck moving at uniform velocity from left to right on a level air table. At the position shown, the puck is given a short, sharp hammer blow B in a direction perpendicular to that in which it is initially moving.

0=puck ( Please ignore parentheses in picture they are there to help aligh picture)

-------------------- 0 ------------------

((()))))))))))))))))))))^ Vi---->

(((((((((())))))))))))))B

A) Show on the figure a trajectory that the puck might follow on the table after the blow is delivered?

My answer - The puck would go exactly 45 degrees to the right (I am not entirely sure - I keep on thinking it is going to go straight)

B) Will the final speed Vi of the puck (immediately after the blow) be equal to, greater than, or smaller than Vi? Explain your reasoning?

My answer - equal to because on a frictionless surface the velocity is never going to change

C) How will the velocity of the puck on the frictionless surface behave as time goes by after the blow? That is, will either the magnitude or the direction of the velocity (or both) keep on changing? If so, how?

My answer = ? (baffled on this part)

I am not sure if my answers are right. I need help understanding the third part for sure. Please correct me if I am wrong for my answers a and b.

This figure is a snapshot looking down on a frictionless puck moving at uniform velocity from left to right on a level air table. At the position shown, the puck is given a short, sharp hammer blow B in a direction perpendicular to that in which it is initially moving.

0=puck ( Please ignore parentheses in picture they are there to help aligh picture)

-------------------- 0 ------------------

((()))))))))))))))))))))^ Vi---->

(((((((((())))))))))))))B

A) Show on the figure a trajectory that the puck might follow on the table after the blow is delivered?

My answer - The puck would go exactly 45 degrees to the right (I am not entirely sure - I keep on thinking it is going to go straight)

B) Will the final speed Vi of the puck (immediately after the blow) be equal to, greater than, or smaller than Vi? Explain your reasoning?

My answer - equal to because on a frictionless surface the velocity is never going to change

C) How will the velocity of the puck on the frictionless surface behave as time goes by after the blow? That is, will either the magnitude or the direction of the velocity (or both) keep on changing? If so, how?

My answer = ? (baffled on this part)

I am not sure if my answers are right. I need help understanding the third part for sure. Please correct me if I am wrong for my answers a and b.

Last edited: