Momentum and impulse question # 2

In summary: The collision causes the heavier object to move and collide with the lighter object. The final velocity of the objects is v=45.4 m/s.
  • #1
Ereny
29
0
an object #1 is motionless and has a mass 10 times greater than the mass of object #2. if object #2 has a velocity of 50.0 m/s before impacting object #1 and if the collision is inelastic determine the final velocity of the objects...

so i am confused do i mult. object #1 by 10 or object #2 i always get confused by 10 times greater than.. and how am i suppose to find velocity without given any masses?
i know i will use (m1v1 + m2v2) before collision = (m1v1 + m2v2) after collision. equation.. but wt do u plug in for m (mass) ?
i really need help..

Read more: momentum and impulse question # 2 | Answerbag http://www.answerbag.com/q_view/2697037#ixzz1q6SWOQvt
 
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  • #2
Ereny said:
so i am confused do i mult. object #1 by 10 or object #2 i always get confused by 10 times greater than..

This should clear that up:

Ereny said:
object #1...has a mass...greater than...object #2.

This is a direct quote from your problem statement. All I did was remove some intermediate words and add boldface for emphasis.
 
  • #3
so that means object #1 is 10 times greater than #2 so i mult object #1 by 10 right?
 
  • #4
Ereny said:
an object #1 is motionless and has a mass 10 times greater than the mass of object #2. if object #2 has a velocity of 50.0 m/s before impacting object #1 and if the collision is inelastic determine the final velocity of the objects...

so i am confused do i mult. object #1 by 10 or object #2 i always get confused by 10 times greater than.. and how am i suppose to find velocity without given any masses?
i know i will use (m1v1 + m2v2) before collision = (m1v1 + m2v2) after collision. equation.. but wt do u plug in for m (mass) ?
i really need help..

Read more: momentum and impulse question # 2 | Answerbag http://www.answerbag.com/q_view/2697037#ixzz1q6SWOQvt

Generally in a problem, if the answer is affected by the ACTUAL mass, you will be told that mass. If you are told, the ACTUAL mass will not make any difference to the final answer sought.

SO ... let object 1 have a mass of 2kg, and thus object 2 have mass 20 kg and see what you get.
If you suspect you shouldn't do that, repeat the problem with masses of 6kg and 60kg to check the final answer is the same.
 
  • #5
Ereny said:
so that means object #1 is 10 times greater than #2
Yes

Ereny said:
so i mult object #1 by 10 right?

No.

If object 1 is 10 times more massive than object 2, then this means you need to take the mass of object 2 (the lighter one) and multiply it by 10 in order to get the mass of object 1 (the heavier one). It's all there in the wording:

"mass 1 is ten times mass 2"

m1 = 10 x m2
 
  • #6
so it will be like this m1v1 + m2v2 = m1v1 + m2v2
1m(0)+ 10m(5om/s) = 11m (v) ??
v= 45.4 m/s ?/?
 
  • #7
Ereny said:
so it will be like this m1v1 + m2v2 = m1v1 + m2v2
1m(0)+ 10m(5om/s) = 11m (v) ??
v= 45.4 m/s ?/?

It should be 10m*0 + m*(50.0 m/s) = 11m*v

The heavier object is the one that is initially motionless.
 

FAQ: Momentum and impulse question # 2

1. What is momentum and impulse?

Momentum is a physical quantity that describes the motion of an object, while impulse is the change in momentum of an object over time.

2. How is momentum calculated?

Momentum is calculated by multiplying an object's mass by its velocity, or p = mv.

3. What is the relationship between force and impulse?

Force and impulse are directly related, as force is the rate of change of an object's momentum over time, or F = Δp/Δt.

4. How does impulse affect an object's motion?

Impulse can change an object's motion by altering its momentum. A larger impulse will result in a greater change in momentum and therefore a larger change in motion.

5. What are some real-life examples of momentum and impulse?

Some examples of momentum and impulse in everyday life include a car crash, a basketball being thrown through a hoop, and a rocket launching into space.

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