Calculating final velocity after a puck is hit

AI Thread Summary
To calculate the final velocity of the puck after being hit by Dave, the Impulse-Momentum Theorem should be applied, considering both the initial velocity and the force exerted. The puck has an initial velocity of 12 m/s directed south and is influenced by a force of 368 N directed N30E for 0.25 seconds. The calculation must account for the vector nature of force and velocity, as the east-west force will only affect the puck's velocity in that direction while the southward component remains unchanged. An initial attempt at the calculation yielded an unrealistic final velocity due to incorrect unit handling and vector consideration. Properly applying the impulse concept will yield a more accurate final velocity for the puck.
kinghunter
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Homework Statement


Bob passes a 0.220kg puck with an initial velocity of 12m/s [South] to Dave. Dave one-times the puck with a force of 368N [N30E] if Daves stick is in contact with the puck for 0.250s what is the final velocity?

Homework Equations


i honestly don't know where to start with this one, if you can tell me what i first need to solve for i should be able to go from there

The Attempt at a Solution

 
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Look in your course notes and/or textbook for "Impulse".

As the question is, it can't be solved, we don't know the initial direction of the puck.
 
billy_joule said:
Look in your course notes and/or textbook for "Impulse".

As the question is, it can't be solved, we don't know the initial direction of the puck.
sorry the initial directon is south
 
kinghunter said:

Homework Statement


Bob passes a 0.220kg puck with an initial velocity of 12m/s [South] to Dave. Dave one-times the puck with a force of 368N [N30E] if Daves stick is in contact with the puck for 0.250s what is the final velocity?

Homework Equations


i honestly don't know where to start with this one, if you can tell me what i first need to solve for i should be able to go from there

The Attempt at a Solution

Hello kinghunter. Welcome to PF !

What quantities are you given? What do you need to find ?

Consider using the Impulse - Momentum Theorem.

You will need to show an attempt before we can give you any more help.
 
i believe the initial velocity when dave hits the puck is 12m/s (carried over from the initial pass), he hits it with a force of 368N [N30E], its in contact with his stick for 0.25s (acceleration period) and the mass of the puck is 0.22kg so what i did is F=ma and a=v/t F=m(vf-vi/t)
vf=F(t)+vi / m
=368N(0.25s)+12m/s / 0.22kg
but then i get an unrealistic number = 472.7m/s
 
kinghunter said:
i believe the initial velocity when dave hits the puck is 12m/s (carried over from the initial pass), he hits it with a force of 368N [N30E], its in contact with his stick for 0.25s (acceleration period) and the mass of the puck is 0.22kg so what i did is F=ma and a=v/t F=m(vf-vi/t)
vf=F(t)+vi / m
=368N(0.25s)+12m/s / 0.22kg
but then i get an unrealistic number = 472.7m/s
For one thing your units are don't work out in several places, partly because you ignore placing parentheses adequately.

Beyond that: Force, velocity and acceleration are all vector quantities. A force in the east - west direction will only cause acceleration in the east - west direction so only changes the component of velocity in the east - west direction. The component of velocity in the north - south direction will remain unchanged at 12 m/s [south] .
 
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