Recent content by circuscircus

Homework Statement A particle moves in the xy plane with constant acceleration. The particle is located at \vec{r} = 2\hat{i} + 4\hat{j} m at t=0s. At t=3s it is at \vec{r} = 8\hat{i} - 2\hat{j} m and has a velocity \vec{r} = 5\hat{i} - 5\hat{j} m/s What is the particle's acceleration vector...

Homework Statement A 20kg loudspeaker is suspended 2 m below the ceiling by two 3m long cables that angle outward at equal angles. What is the tension in the cables? Homework Equations The Attempt at a Solution cos theta = 2/3, theta=48.2 degrees w=mg=20kg * 9.8m/s^2 = 196N...

Homework Statement A 1000kb steel beam is supported by two ropes. Each rope as a maximum sustained tension of 6000N. Does either rope break? If so, which one(s)? http://img101.imageshack.us/img101/3930/diagramgm2.jpg Homework Equations Tension = M cos/sin theta (in this case it is...

Homework Statement http://img413.imageshack.us/img413/226/8m1celf4.gif On b, why is the pi exp 3.18 +- 0.04 and not .012? Homework Equations The Attempt at a Solution

So the real F is sqrt(130^2+30^2) am I correct?

So then is arctan(30/190) 9 degrees? (I don't have access to a radian calculator right now), also how do they get the 19N?

Homework Statement http://img61.imageshack.us/img61/4585/8m1cdhx1.gif I understood every except, How do they get the 9 degrees in part c? Homework Equations The Attempt at a Solution

Homework Statement THe bus is D=10m ahead of the person and accelerates from rest at a=2m/s^2 while the person runs after it at 7m/s. Suppose D is not specified, what maximum distance can the bus be ahead of the person that will allow the person to catch the bus? Homework Equations...

Well the area under the chart is 8 at 4 seconds but that's the vi so how doe sthat come into play?

http://img215.imageshack.us/img215/5994/freefallgn3.jpg sometimes it helps to reduce error and make life easier to plug in the x = vi t + 1/2 at^2 formula into the quadratic equation first and simplify before plugging in the actual values... this approach makes life easier for some ppl

Well integrating the acceleration gets you velocity, does it not?

Homework Statement The graph shows acceleration versus time of a particle moving along the x axis. Its initial velocity is 8m/s at t=0. What is the particle's velopcity at t=4s? http://img259.imageshack.us/img259/6684/graphcc9.jpg Homework Equations The Attempt at a Solution...

Homework Statement A speed skater moving across frictionless ice at 8m/s hits a 5m patch of ice. She slows steadily then continues at 6m/s. What is her acceleration on the rough ice? Homework Equations Not sure The Attempt at a Solution 6m/s - 8m/s = -2m/s * 1/5m = 1/10 s...

s1 + s2 = 100 s1 = 1/2 * 40 t s2 = 1/2 * 60 t s1 = 100-s2 100 - s2 = 1/2 *40 t s2 = 1/2 * 60 t s2 = - 1/2 *40 t + 100 s2 = 1/2 * 60 t -20t + 100 = 30t 10t = 100 t=10 (5*40 + 5*60 ) /10 (200+300)/10 = 50 mph So basically like this?

Homework Statement Julie drives 100mi to Grandmother's house. On the way to Granmothers, Julie drives half the distance at 40mph and half the distance at 60mph. On the returntrip, she drives half the time at 40mph and half at 60mph. What is her average speed on the return trip...