Hey, I'm sorry to bombard you with questions, but I've been out of my Physics lecture due to lots of work from other classes, and I've got these 3 questions which I have no idea how to do. Our professor does not teach according to our textbook, and I'm too thick to understand these concepts. Any help would be very, very appreciated.(adsbygoogle = window.adsbygoogle || []).push({});

1. a. Two objects have masses of M and 3M, respectively. If both have the same kinetic energy, which one has the larger linear momentum and by what factor? Why?

b. If the two objects have the same linear momentum (magnitude), which will have the larger kinetic energy and by what factor? Why?

2. You drop a ball of mass 1 kg from a height of 2m. The collision with Earth lasts for about 10^-4 seconds and on bouncing the ball rises to a height of 1.5m. Is this collision totally elastic? Why?

3. A person of mass 50 kg is standing at the end of a plank of mass 100 kg and length 5m and the plank rests on a horizontal smooth, icy surface. If the person walks from one end to the other, by how much will the plank move? Why?

2.KE= 1/2m(p/m)^2=(p^2)/2m, (v1'-v2')=(v2-v1)=-(v1-v2)

3.(1) I'm really trying to understand 1, because I had thought that two objects with the same momentum, but different masses would have different kinetic energies. I don't think that I can really apply this, though.

(2) I'm thinking that it's not, because in an elastic collision, the KEs should be the same? On second thought, I don't know this at all, either.

(3) I don't know where to start with this.

I'm sorry for my idiocy.

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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# Homework Help: Linear Momentum/Kinetic Energy

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