EvoN1020v

One thing: I mistype the value of acceleration, it should be [math]1.0 m/s^2[/math] instead. Therefore, the applied force ([math]F_{app}[/math]) would be 15 N. First thing I did: Find the friction Force when the boy push the 15 kg box. [math]\sum F_x = F_{app} - F_f - (F_g)_x = ma[/math] [math]F_f = F_{app} - (F_g)_x - ma[/math] [math]F_{app}[/math] and [math]-ma[/math] cancel each other, so that remains [math](F_g)_x[/math] which is [math]mgsin30[/math]. The friction force is: [math]73.575 N[/math]. What I do next? I know that the friction force is greater than the applied force but, he have a mass of 40 kg, so I'm not sure how to join that reference to figure out my answer? Maybe I should figure out the [math]F_{fsmax}[/math] for his shoe to the ground? Any help here please?

The amount of sleep a person needs also increases if he or she has been deprived of sleep in previous days. Getting too little sleep creates a "sleep debt," which is much like being overdrawn at a bank. Eventually, your body will demand that the debt be repaid. We don't seem to adapt to getting less sleep than we need, while we may get used to a sleep-depriving schedule, our judgment, reaction time, and other functions are still impaired. Many studies make it clear that sleep deprivation is dangerous. Sleep-deprived people who are tested by using a driving simulator or by performing a hand-eye coordination task perform as badly as or worse than those who are intoxicated. Sleep deprivation also magnifies alcohol's effects on the body, so a fatigued person who drinks will become much more impaired than someone who is well rested. Driver fatigue is responsible for an estimated 100,000 motor vehicle accidents and 1500 deaths each year, according to the National Highway Traffic Safety Administration. Since drowsiness is the brain's last step before falling asleep, driving while drowsy can—and often does—lead to disaster. Caffeine and other stimulants cannot overcome the effects of severe sleep deprivation. The National Sleep Foundation says that if you have trouble keeping your eyes focused, if you can't stop yawning, or if you can't remember driving the last few miles, you are probably too drowsy to drive safely. Chemcial properties of sleeping that rthmjohn request: Circadian rhythms are regular changes in mental and physical characteristics that occur in the course of a day (circadian is Latin for "around a day"). Most circadian rhythms are controlled by the body's biological "clock." This clock, called the suprachiasmatic nucleus or SCN, is actually a pair of pinhead-sized brain structures that together contain about 20,000 neurons. The SCN rests in a part of the brain called the hypothalamus, just above the point where the optic nerves cross. Light that reaches photoreceptors in the retina (a tissue at the back of the eye) creates signals that travel along the optic nerve to the SCN. Signals from the SCN travel to several brain regions, including the pineal gland, which responds to light-induced signals by switching off production of the hormone melatonin. The body's level of melatonin normally increases after darkness falls, making people feel drowsy. The SCN also governs functions that are synchronized with the sleep/wake cycle, including body temperature, hormone secretion, urine production, and changes in blood pressure. Source: http://www.medicinenet.com/sleep/page5.htm

Anyone?

I apologize for my tardiness, because I have been busy with scholarships lately. Here is the next question: A right triangle in the first quadrant is bounded by lines y = 0, y = x, and y = -x+5. Find its area. I know this is a easy math question, but I'll post harder one next time.

Thanks 5614. I got another challenging physcis question for you guys: A 40 kg boy works at his dad's hardware store. One of the boy's jobs is to unload the delivery truck. He places each package on a 30 degrees ramp and shove it up the ramp into the storeroom. He needs to shove the package with an acceleration of at least 0.1 m/s^2 in order for the package to make it to the top of the ramp. One day the ground is wet with rain and he's wearing slick leather-soled shoes. The coefficient of static friction between his shoes and the ground is 0.25. The largest package of the day is 15 kg, and it's coefficient of static friction on the ramp is 0.40. Can he give the package a big enough shove to reach the top of the ramp without his feet slipping?

You need to sleep to refresh your brain to stay awake for another 14 to 18 hours per day. Use the image of a battery charger for cellphones, it's kind of the same thing for our brain. (i.e. balance of chemicals). If you don't sleep enough, then you'll get physcially abused from your lack of mental power. You'll get very detorieted.

MIT greatly depend on your school GPA. Also, your involvment in community and school activities/clubs.

If you have to let go of your car at one point, and not allowed to touch it while it is in motion. Well, I did a similiar project at DAL (Dalhousie University) for enterainment. I recommend you to take many balloons as you can, and join it to straws, and get all the straws to join together. Then, the air from the balloons would blow out a specific hole and it should give you the maximum power projection. Also, make sure the car's wheels are very lubractive, as if there almost is no friction.

You can find it yourself on Google. Also, you can ask your guidance counselor for help.

Can anybody answer my question?

You'll have to do a lot of research if you want a science project to be in the field of Chemistry and/or Physics. I recommend you to go googling for Fun Chemistry Projects. You can tell us some ideas if you have any, and we can help you expand the ideas. Ok?

So you're saying that I'm correct? Are the values accurate comparing to yours?

I have another question: A 1.0 kg wood block is pressed against the wood wall by the 12N force down. If the block is initially at rest, will it move upward, move downward, or stay at rest? (The coefficient of static friction for wood is 0.50 and the coefficent of kinetic friction is 0.20). My answer is that the block won't move, because the resultant vector ([math]V_{r}[/math]) is lesser than [math]F_{fsmax}[/math], where [math]V_{r} = 3.81 N[/math], and [math]F_{fsmax} = 5.196 N[/math]. Am I correct?

It should have been [math]n = log_r(1 - \frac{S_{n}(1-r)}{a})[/math]. It will yield [math]n = 1.169926444[/math]. For those who are in confusion: r = 0.5; a = 90; Sn = 100.

I see.

I recommend you not to drink excessive water before or during exercising. You should just wet your mouth and shallow a small amount down your throat. I'm a wrestler, so I drink a lot of water. During my intense 2 hours practises, we are given some water drinks. During my first novice days, I drank excessive water, and it gave me cramps right away. Now, I just wet my mouth and drink a small amount. Then, after the exercise you can drink much water as you want.

Never seen a SATA before. I have been fixing computers in school for 2 years now and I have seeing the PATA cables all the time. Guess I'm not updated with modern computer technology. But then again, I assume those SATA cables are more expensive than PATA cables right? Also, how does the hell PATA cables would fit the slots in the motherboard? It has to be wide to fit in the slots?

Hello? Are you dead?

Whoops. Pardon for all the [math]\cos[/math], as they should be [math]\sin[/math]. It's too late to edit my post, so thanks 5614 for the warning.

I got [math]log_{0.5}-0.444444[/math] So the answer have a negative number, so "math ERROR" appeared on my calculator. Any help please?

I assume it's not an illicit substance?

What is Caramacs? I looked in the dictionary, but couldn't find anything, so I assume it's a name brand of something. What is it?

[math]\sum{F_{x}} = (F_{a})_{x} - (F_{b})_{x}[/math] [math]Acos12 - Bcos12 = 0[/math] [math]cos12(A-B) = 0[/math] [math]\frac{cos12(A-B)}{cos12}[/math] [math](A-B) = 0[/math] [math]A = B[/math] Let A = B = T (Tension). [math]\sum{F_{y}} = (F_{a})_{y} + (F_{b})_{y} - F_{g} = 0[/math] [math]Asin12 + Bsin12 - 637.65N = 0[/math] [math]sin12(A+B) - 637.65N = 0[/math] [math]sin12(T+T) - 637.65N = 0[/math] [math]2Tsin12 - 637.65N = 0[/math] [math]2Tsin12 = 637.65N[/math] [math]T=\frac{637.65N}{2(sin12)} = 1.5x10^3N[/math] Both of the ropes are equal, so the answer of [math]T_{1}[/math] and [math]T_{2}[/math] is: [math]1.5 x 10^{3} N[/math].