How Do You Calculate Final Velocity and Change in Momentum for a Moving Body?

[phyzacs]

hi guys I am a college junior...taking physics for the first time in my life...its fun...but still tuff...just can i get help with these couple questions..i mean it would be very gracious of any of u to help me out...i know I am new and all, but this place...i was just browsing around and it rocked sooo...and

wow i never new this place existed...i might come here much more often


question 1: a 3.0 kg body is initially moving northward at 15m/s. Then a force of 15N, towards the east acts on it for 4.0 s (a) At the end of the 4.0 s, what's the body's final velocity? (b) what is the change in momentum during the 4.0 s?


i know the answers...can you just show me how to work out part A? i got 60 for part B, and keep getting 25 for part A, but that's not it...

i would really appreciate this...thank you...illpost the other 3 questions as well ?

 

[phyzacs]

The position of three particles written as (x,y) coordinates are, particle 1 (mass 4.0 kg) at (4.0m, 0m); particle 2 (mass 6.0kg) at (2.0m, 4.0m); particle 3 (mass 3.0 kg) at (-1.0m, -2.0) what is the location of the center of mass?


this one too pleasE?? how do you do it...i have answers...

 

[phyzacs]

A projectile of mass 2.0 Kg approaches a stationary target body at 8.0 m/s. The projectile is deflected through an angle of 90.0 degrees and its speed after the collision is 6.0 m/s. WHat is the speed of the target body after the collision is perfectly elastic?


any help on how to do this one guyzz??

 

[phyzacs]

The position of three particles written as (x,y) coordinates are, particle 1 (mass 4.0 kg) at (4.0m, 0m); particle 2 (mass 6.0kg) at (2.0m, 4.0m); particle 3 (mass 3.0 kg) at (-1.0m, -2.0) what is the location of the center of mass?


this one too pleasE?? how do you do it...i have answers...

ok i solved this one, so don't need it thanks...

 

[tjlaxs]

question 1: a 3.0 kg body is initially moving northward at 15m/s. Then a force of 15N, towards the east acts on it for 4.0 s (a) At the end of the 4.0 s, what's the body's final velocity?

Considering this is propably one of the easiest exercise you can make of Newton's second law and constant acceleration, you should really try solving it again. Keywords: Newton's second law and motion with constant acceleration ;)

 

[phyzacs]

brother i am doing it,...the answer i am getting is 35...teacher says it is 25...what am i doing wrong inthe calculations?

 

[Integral]

Perhaps, if you showed us your solution, we could help find the error.

Also, we have a homework help forum, just for this type of post.

 

[tjlaxs]

brother i am doing it,...the answer i am getting is 35...teacher says it is 25...what am i doing wrong inthe calculations?

My guess is you are forgetting that the directions of the two velocities are different (first 15m/s to north and second caused by the force is to east).