I have gotten this answer wrong, I cannot figure this out please help!!! As show
ID: 1335963 • Letter: I
Question
I have gotten this answer wrong, I cannot figure this out please help!!!
As shown in the figure below, object m1 = 1.45 kg starts at an initial height h1i = 0.255 m and speed v1i = 4.00 m/s, swings downward and strikes (in an elastic collision) objectm2 = 4.50 kg which is initially at rest. Determine the following.
(a) speed of m1 just before the collision.
2.96- this is wrong!!!
After you are convinced that energy is conserved as m1 swings downward for the collision with m2, see if you can write a statement of conservation of energy that will allow you to determine the speed of m1 as it collides with m2. m/s
(b) velocity (magnitude and direction) of each ball just after the collision (Assume the positive direction is toward the right. Indicate the direction with the sign of your answer.)
-1.15 is wrong and 1.95 is wrong
We have been informed that the collision is elastic and since no external forces are involved in the collision, momentum is also conserved. See if you can write a statement of conservation of momentum and a statement of conservation of energy which can be combined to obtain the final velocity of each mass. m/s (m1)
We have been informed that the collision is elastic and since no external forces are involved in the collision, momentum is also conserved. See if you can write a statement of conservation of momentum and a statement of conservation of energy which can be combined to obtain the final velocity of each mass. m/s (m2)
(c) height to which each ball swings after the collision (ignoring air resistance)
m_1=
m_2=
Explanation / Answer
(a) Speed of mass m1 before the collision
we will apply the conservation of energy
Initial energy = m1gh + (1/2)m1V2
Final energy = (1/2)m1V12
Equating both equation we get
V1 = 4.5829 m/s
(b)
We will apply conservation of momentum
m1V1 = m1V1f + m2V2f
1.45*4.5829 = 1.45*V1f + 4.5V2f
now second equation of energy
(1/2)m1V12 = (1/2)m2V22f + (1/2)m1V1f2
from first equation we get
6.645 = 1.45V1f + 4.5V2f
from second equation
15.227 = .725V1f2 + 2.25V22f
Putting V2f in the second equation from first
we get
0.956V1f2 -2.1386 V1f -10.2984 = 0
so we get V1f = -2.348 m/s
And V2f = 2.232 m/s
(c) gh = V1f2 /2
h1 = .2809m
h2 = 0.2539 m