Physics (10 Points for First Correct Answers)Five Stars !?

Energy : Our heart uses energy to beat. Energy is the source of all work and no matter what do you do your body needs energy. But it is not only living things that need energy to work. - for exanple our machine have to make use of a source of energy in order to do its jobs for which they may be designed. Energy can be thought of like a world bank for work in which there are many sources of energy just as there are many sources of money, each exchangeable with another. in case of money it might be dollars, pounds or yen that are exchange and then stored and used in various ways. In the case of energy the currencies are things like electricity, heat sunlight, air. The golden rule to remember is that energy is always change from one form to another and never lost. Resistance: Any force tend to hinder motion. In the mechanical energy the Resistance in motion are called friction which are usually measured in pound or kilo grams. There are also resistance in the electrical energy flow which are called Resistance usually measured in ohms. Cost: Price paid for anything. Any thing that the mechanical or electrical energy uses needs money so to ballance the ecconomy the production are sold. Take for example the electricity we use in our homes cost money. It is ussually sold in its power used per hour or second. That is watts or kilowatts per hour or second. Current : A movement or flow of electricity. When talking about current it is always associated with electrical energy. Where this electrical energy are made to flow to a conductors or simply wire in order that this energy can be use to light our houses, run our appliances and etc. So this movement of electrical energy are termed as Current.

1. Period of motion for oscillating board?

You are mistaken in at least one thing you have put forward in the problem statement. The reason that the originator of this problem intimated that the board would oscillate is because the friction does not stay constant. As the board is to the right the friction on the board on the right will be higher than the friction between the left roller and the board due to the fact that the right hand roller will support more of the weight. The thing that is constant is the factor that is the ratio of frictional force to the vertical force of the board on the roller. There is of course another assumption not stated that the board is significantly longer than the distance between the rollers. At least the oscillation can not be allowed to have one end of the board drop off the roller.

2. Proving Brownian motion is not monotone

Your argument is correct. It is true that $P(B_a_i-B_a_i1>0)=1/2$, because the random variable $B_a_i-B_a_i1$ is normally distributed with mean zero.(We typically consider the increments in the form $B_a_i1-B_a_i$, where we subtract the earlier value of $B$ from the later value of $B$, but the argument you've posed is still correct.)

3. is light an example of perpetual motion?

Not sure about that but air is an example of perpetual motion

4. Safety in heavy landmine squats and presses

As mentioned in the comments, landmines exercises are about as safe as anything. Having said that, there are some precautions worth taking if you are concerned:Make sure your base is secure. If you are using a plate post, make sure it's heavy enough, and does not slide. Bumper plates are great, as they stick to the floor to prevent sliding (got that tip from Dean over at Black Widow Training). In my gym at home, I normally use a cheap 10 lbs bumper with a 45 on top (if I am driving hard, I may throw on an additional 45 for good measure). If you are using a rack mounted landmine, or a safety pipe pivot system (more on that in a moment), you are in good shape (I've been using the Hammer Strength HD Elite landmines lately, and they are bomb proof. As mentioned, landmines are relatively easy to dump if things get hairy, but does not hurt to be more prudent. Set up a bench underneath the bar. Place it so it's high enough to catch during a failed rep, but low enough as to not interfere with full range of motion. Just make sure the bench is not set so low that the post pops outs of the plate stack (e. g. , doing heavy Viking presses). If you have a safety pipe pivot attachment for your power rack (I've used both Black Widow's and Titan's on my Rogue R4 rack with great success...they are relatively inexpensive; around $15), you can really dial in the safety. Set the pivot on one end of the rack, and the opposite side safety pipe on the other. You can dial in your range of motion within 2" (1" with Westside holes). Of course there's the matter of losing control in the transverse plane...ability to work in the transverse plane is what makes landmines so unique (i. e. , oblique twists), but if you are doing a sagittal movement (e.g., press, squat), you can, once again, use the pivot system to ensure it's locked into a path and does not veer off to the left or right. If you do not have a rack, just make sure your bench is long enough, and you are being responsible with your weight selection (do that anyway).