# Search results

1. ### Chair leg pressure problem geez

Goofy err on my part. Actually had the answer correct the first time with 1442774.68 but posted my answer as 1.4E6....the correct way to post my answer was 1.44E6 Thank you
2. ### Chair leg pressure problem geez

Chair leg pressure problem....geez Homework Statement A 63kg person sitting on 3.5kg chair. Four legs contact the floor, each leg with circle 1.2cm in diameter. Find pressure exerted on floor by each leg of chair (weight evenly distributed). Homework Equations [{(person mass) +...
3. ### Formula Derivation

Thanks mezarashi...that is what I was thinking also of Ffrict = mg x f ... however, to come up for the correct answer for the problem it was neccesary to use mg/f ..... just could not understand why the mg was divided by f rather than multiplied.
4. ### Formula Derivation

In solving the problem of the least force needed to hold a board against the wall to prevent it from sliding down when the cof is known...the formula of F=mg/f was used to come up with the correct answer. Having found this formula in solving the problem it would be beneficial to also understand...
5. ### Apollo 13 and bad physics

...being a simple fellow, I would think that using sound effects in space is bad physics due to a vacuum does not transmit sound. So stuff fly by would do so quietly...
6. ### Increase in speed, decrease in time

...after sleeping on this I got it figured out.
7. ### Running the red light (car physics)

Never mind the mass of the car...you will not need if for the calculations you are trying to figure out. Here are some formulas to use... Speed = square root of (30df) 30 is a constant resulting in the derivation of this formula. d is the distance if the vehicle is sliding (skidding) to a...
8. ### Increase in speed, decrease in time

Please forgive me for trying to exercise my 50+ year old mind to keep alzheimer's at bay...by working on physics problems. I came across this problem and tried to solve for "t" ending up with t= 37 seconds. It was at this point that I got a brain "phart". (sorry) I am lost. What am I not...
9. ### Help with visualizing this problem

Thanks! Woke up this morning realizing that I was over thinking this problem. Casey
10. ### Help with visualizing this problem

Help with visualizing this problem.... I am having a bit of brain lock-up at the moment...and just can not seem to see my way through this problem. A vehicle takes "t" to travel one mile. If the vehicle's speed was 5 mph faster then the "t" to travel the one mile would of been 11 seconds...
11. ### Cube Deceleration Problem

Got it! Thanks... Casey
12. ### Cube Deceleration Problem

A 0.5m cube is sitting on top, and at the end, of a 1m wide by 3m long board. Both the cube and board are traveling at a constant velocity of 10 m/s. The board begins to decelerate at -8.5 m/s squared. The cube decelerates across the top of the board at -3 m/s squared. How much time will it take...
13. ### Sliding Blocks Problem

Two blocks, a one foot cubic block in sitting on top a four foot cubic block. Both blocks are moving forward at 36 fps and instantly begin to decelerate...the larger block with cof of .9 (-28.98 fps/sqr) and the top block with cof of .3 (-9.66 fps/sqr). Trying to determine the time/distance...
14. ### Car vs pedestrian collision

This physics problems has me stumped....a vehicle is braking at the time of a collision with a pedestrian. The vehicle is decelerating on a coefficient of friction (cof) of a 0.88. The vehicle and pedestrian reach a common velocity at the windshield of 35 fps. The pedestrian decelerates...