4. 11 points MI4 3.12.053. My Notes O Ask Your Object A has mass mA = 9 kg and i

Question

4. 11 points MI4 3.12.053. My Notes O Ask Your Object A has mass mA = 9 kg and initial momentum/AJ momentum B,,-€3, 6, 0 > kg·m/s. 21,-7, 0 > kg . m/s, just before it strikes object B, which has mass mB = 13 kg. Just before the collision object B has initial Consider a system consisting of both objects A and B. What is the total initial momentum of this system, just before the collision? kg m/s sys,= The forces that A and B exert on each other are very large but last for a very short time. If we choose a time interval from just before to just after the collision, what is the approximate value of the impulse applied to the two-object system due to forces exerted on the system by objects outside the system? N-S Therefore, what does the Momentum Principle predict that the total final momentum of the system will be, just after the collision? kg m/s sys,f = Just after the collision, object A is observed to have momentum PAf= kg·m/s. what is the momentum of object B just after the collision? kg - m/s Additional Materials Section 312

Explanation / Answer

Momentum is a vector and you are given the three components of each objects momentum vector;

PAi = (21)i - (7)j + (0)k

PBi = (3)i + (6)j + (0)k

a) Just add the two vectors (add components algebraically) to get the total initial momentum, Pi.(which will be expressed as three components like the other momentums) <21+3, -7+6, 0> = <24, -1, 0>kg m/s

b) There is no mention of forces exerted by outside objects. Assume that there aren't any (because none stated) so the value of their impulse is zero.they asked for impulse -- this depends on knowing the amount of time it takes for a change in momentum to occur. They don't give you this amount of time, and there is no way to calculate it from given info.

c)Momentum is conserved. So this is the same as the answer to question A (momentum before collision = momentum after) .

D. Here also momentum is conserved. So if object A has momentum of <17, 5, 0 > the components of object B must add with it to get the total of < 24, -1, 0 > .Rearrange this algebraically starting from <17, 5, 0 > + < x, y, z > = < 24, -1, 0 >, therefore 17 + x = 24 ,x = 7, and 5 + y = -1 ,y = -6. So the answer is < 7, -6, 0 > kgm/s

Related Questions

Navigate

• Browse (All)
• Browse 4
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.