course Phy 201 I need to find the area again to see the review of my work. ЗIE\gឲPخ
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11:47:15 Intro Prob 6 Intro Prob 6 How do you find final velocity and displacement given initial velocity, acceleration and time interval?
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RESPONSE --> First displacement must be found ds= v0*dt+.5a*dt After finding displacement, the Vave can be found vAve= ds/dt Next, is finding the dV vAve*dt= dv Velocity Finval is finally found. vf= v0+dv confidence assessment: 3
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11:49:14 ** To find final velocity from the given quantities initial velocity, acceleration and `dt: Multiply `dt by accel to get `dv. Then add change in velocity `dv to init vel , and you have the final velocity**
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RESPONSE --> I understand this way, but would the way i explained work as well? self critique assessment: 3
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11:51:27 Describe the flow diagram we obtain for the situation in which we know v0, vf and `dt.
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RESPONSE --> what are you asking for the flow digram to find? confidence assessment: 0
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11:53:32 ** The flow diagram shows us the flow of information, what we get from what, usually by combining two quantites at a time. How we get each quantity may also be included. From vf and v0 we get `dv, shown by lines from vf and v0 at the top level to `dv. From vf and v0 we also get and vAve, shown by similar lines running from v0 and vf to vAve. Then from vAve and `dt we get `ds, with the accompanying lines indicating from vAve and `dt to `ds, while from `dv and `dt we get acceleration, indicated similarly. **
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RESPONSE --> self critique assessment: 3
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12:05:09 Principles of Physics and General College Physics Students: Prob. 1.26: Estimate how long it would take a runner at 10 km / hr to run from New York to California. Explain your solution thoroughly.
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RESPONSE --> It is roughly 3500km from NY to Ca 3500km*10km/hr= 35000km/?hr 35000/60 =583.33hrs or 24 days for the runner to run from NY to Ca. confidence assessment: 1
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12:10:25 It is about 3000 miles from coast to coast. A km is about .62 mile, so 3000 miles * 1 km / (.62 miles) = 5000 km, approximately. At 10 km / hr, the time required would be 5000 km / (10 km / hr) = 500 km / (km/hr) = 500 km * (hr / km) = 500 (km / km) * hr = 500 hr.
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RESPONSE --> self critique assessment: 3
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12:27:29 All Students: Estimate the number heartbeats in a lifetime. What assumptions did you make to estimate the number of heartbeats in a human lifetime, and how did you obtain your final result?
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RESPONSE --> I estimated that the heart would beat approximately 3,000,000,000 beats in a lifetime average person lives to about 75 (27375 days) I asumed that the average heartbeat was 75beats/min 75*60min= 4500beats/hr 4500 * 24hr= 108000 beats/ day 108000* 27375 days = aprox. 3,000,000,000 beats/lifetime confidence assessment: 3
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12:29:48 ** Typical assumptions: At 70 heartbeats per minute, with a lifetime of 80 years, we have 70 beats / minute * 60 minutes/hour * 24 hours / day * 365 days / year * 80 years = 3 billion, approximately. **
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RESPONSE --> self critique assessment: 3
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12:30:03 University Physics Students Only: Problem 1.52 (i.e., Chapter 1, Problem 52): Angle between -2i+6j and 2i - 3j. What angle did you obtain between the two vectors?
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RESPONSE --> confidence assessment: 0
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12:30:27 ** For the given vectors we have dot product =-2 * 2 + 6 * (-3) = -22 magnitude of first vector = sqrt( (-2)^2 + 6^2) = sqrt(40) magnitude of second vector = sqrt( 2^2 + (-3)^2 ) = sqrt(13) Since dot product = magnitude of 1 st vector * magnitude of 2d vector * cos(theta) we have cos(theta) = dot product / (magnitude of 1 st vector * magnitude of 2d vector) so that theta = arccos [ dot product / (magnitude of 1 st vector * magnitude of 2d vector) ] = arccos[ -22 / ( sqrt(40) * sqrt(13) ) ] = arccos ( -.965) = 164 degrees, approx.. **
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RESPONSE --> self critique assessment: 0
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12:30:52 Add comments on any surprises or insights you experienced as a result of this assignment.
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RESPONSE --> self critique assessment: 3
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12:31:16 ** I had to get a little help from a friend on vectors, but now I think I understand them. They are not as difficult to deal with as I thought. **
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RESPONSE --> self critique assessment: 3
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BՅc۫˩x assignment #005 005. `query 5 Physics I 03-10-2008