- #1
Nash77
- 9
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Attached is my practice physics final. I need help! Below are my attempts at solutions... probably way off but maybe I just need a head start. Thanks for looking!
PS We are told to use 10 m/s^2 for gravity.
--Nash.
III.
1) at the top, all potential energy = mgh = 1*10*6 = 60
at the break point P: total energy = 60 = mgh + 1/2mv^2 = 1*10*1 + 1/2*1*v^2
60 = 10 + 1/2*1*v^2 50 = 1/2*1*v^2 10 = v
It is moving horizontally to the right when it breaks.
2) how far will the block travel?
Can I figure this out without time? I tried to use different formulas and got 5m, but I think that's wrong. I mixed up Vx with Ay so I think it's wrong.
IV.
KE of bullet = 1/2*0.01*100^2 = 50 J
I tried using conservation of energy, so KE for the bullet = 50 = KE for the Mass = 50 J
I got a height of 5.05 when this KE turns into PE for the Mass, but I'm sure it's not right to say KE is conserved... how do you know how much of it transfers to the Mass when the bullet gets lodged in the block of wood?
V.
1) Only two forces acting in the vertical direction, Weight acting down and Tension acting up. The weight = mg = 1*10 = 10 N. So the Tension should be the same, equal and opposite, since the rod is at rest. So Tension should be 10 N also, just acting up whereas weight is acting down. Is this correct, or do I need to take components of the tension?
2.) I said no force exerted by the wall, since there is no motion in the horizontal direction. Weight works down, so this shouldn't affect a rod attached perpendicular to the force of gravity.. but can there really be no force?
3.) Linear Velocity? moment of inertia = 1/3ML^2 = 1/3*1*1^2 = 1/3,
I know that Torque force = I*alpha (angular acceleration.) But how does angular acceleration relate to linear acceleration? How would I find either in this problem? Am I way off track here?
VI.
I'm going to try to work on this one now. Any suggestions would be much appreciated.
Thanks for having patience with all of this... PS Don't be too harsh.. Physics isn't my best subject if you couldn't tell ;) Still, I'm willing to learn!
PS We are told to use 10 m/s^2 for gravity.
--Nash.
III.
1) at the top, all potential energy = mgh = 1*10*6 = 60
at the break point P: total energy = 60 = mgh + 1/2mv^2 = 1*10*1 + 1/2*1*v^2
60 = 10 + 1/2*1*v^2 50 = 1/2*1*v^2 10 = v
It is moving horizontally to the right when it breaks.
2) how far will the block travel?
Can I figure this out without time? I tried to use different formulas and got 5m, but I think that's wrong. I mixed up Vx with Ay so I think it's wrong.
IV.
KE of bullet = 1/2*0.01*100^2 = 50 J
I tried using conservation of energy, so KE for the bullet = 50 = KE for the Mass = 50 J
I got a height of 5.05 when this KE turns into PE for the Mass, but I'm sure it's not right to say KE is conserved... how do you know how much of it transfers to the Mass when the bullet gets lodged in the block of wood?
V.
1) Only two forces acting in the vertical direction, Weight acting down and Tension acting up. The weight = mg = 1*10 = 10 N. So the Tension should be the same, equal and opposite, since the rod is at rest. So Tension should be 10 N also, just acting up whereas weight is acting down. Is this correct, or do I need to take components of the tension?
2.) I said no force exerted by the wall, since there is no motion in the horizontal direction. Weight works down, so this shouldn't affect a rod attached perpendicular to the force of gravity.. but can there really be no force?
3.) Linear Velocity? moment of inertia = 1/3ML^2 = 1/3*1*1^2 = 1/3,
I know that Torque force = I*alpha (angular acceleration.) But how does angular acceleration relate to linear acceleration? How would I find either in this problem? Am I way off track here?
VI.
I'm going to try to work on this one now. Any suggestions would be much appreciated.
Thanks for having patience with all of this... PS Don't be too harsh.. Physics isn't my best subject if you couldn't tell ;) Still, I'm willing to learn!