<p>PLEASE HELP ME....I HAVE BEEN OUT OF SCHOOL FOR TWO WEEKS AND I AM LOST IN PHYSICS...MY EMAIL ADDY IS <a href="mailto:nubianprince05@aol.com">nubianprince05@aol.com</a></p>
<p>I HAVE LIKE OVER 12 PAGES TO COMPLETE AND I KNOW NOTHING...</p>
<p>IM BEGGING</p>
<p>1) Find the heat energy required to raise the temperature of a 2000 g ice block from-5.00 degrees C to steam at 120 degrees C.</p>
<p>2) A 4.0 kg block stretches a spring 6.0 centimeters. What is the spring constant in newtons per meter? How much work is being done to stretch the spring?</p>
<p>3) A solid copper rod at 20 degrees C is 80 cm long and 2.8 cm wide. The resistivity of copper at 20 degrees is 1.7x10^-8{ m. Find the resistance between the two ends.</p>
<p>isnt there anyone at school u could ask?</p>
<p>my physics teacher is an idiot....she just got out of college and can do ontihng but read directly from the book and give assignments...im doomed</p>
<p>I'll get you started. Here's #1.</p>
<p>1.)
This problem is actually very simple. You only use two equations here: Q=mcT to get the heat needed to create a certain temperature change without a phase change, and Q=mL to get the heat needed to change the phase of a substance. You need to do this multiple times, then add up the total heat (Q) needed. </p>
<p>m is given, T is easy to figure out from looking at how much temperature change must occur between each phase change, and c and L are constants. Just plug in and solve.</p>
<p>2000g = 2kg</p>
<p>Q1=mcT
Q1=(2)(2090)(5)
Q1= 20900 J</p>
<p>Q2=mLf
Q2=(2)(3.35x10^5)
Q2= 670000 J</p>
<p>Q3=mcT
Q3=(2)(4186)(100)
Q3= 837200 J</p>
<p>Q4=mLv
Q4=(2)(2.26x10^6)
Q4= 4520000 J</p>
<p>Q5=mcT
Q5=(2)(2010)(20)
Q5= 80400 J</p>
<p>Q1+Q2+Q3+Q4+Q5 = 6069000 J = 6069 kJ</p>
<p>(Someone plz check this answer for me to make sure I did the math correctly)</p>
<p>Good luck on your makeup work</p>
<p>2) A 4.0 kg block stretches a spring 6.0 centimeters. What is the spring constant in newtons per meter? How much work is being done to stretch the spring?</p>
<p>Use Hooke's Law here: F = kdx</p>
<p>4(9.81) = k * .006</p>
<pre><code> k = 6540 N/m that's your spring constant
</code></pre>
<p>For the second part use W = f * d</p>
<p>W = 4(9.81) * .006</p>
<p>W = 0.23544 Joules</p>
<p>There you go. I don't need any money; I'm just happy to help.</p>
<p>2) Pentasa, 6.0cm = 0.06m, so your answers are off by a factor of 10. k = 653 N/m and W = 2.35 Joules</p>
<p>3) A solid copper rod at 20 degrees C is 80 cm long and 2.8 cm wide. The resistivity of copper at 20 degrees is 1.7x10^-8{ m. Find the resistance between the two ends.</p>
<p>R = rho * L / A where R = resistance, rho = resistivity, L = length, and A = area. Since we have a rod, A = pi<em>r^2. So R = (1.7E-8)</em>0.80/(pi*0.014^2) = 2.21E-5 ohms</p>
<p>Thanks soooooo much guys....I really appreciate the help..i know you have homework too</p>
<p>can anyone show me how to do this? please</p>
<p>11) A man who is 0.268 kilometer away from a cliff strikes a spike with a sledge hammer. The wavelength of the sound produced by the spike is 0.250 meter. Assume the speed of sound on this day is 335 meters per second.</p>
<p>a) How long does it take for the sound to travel to the cliff and reflect to produce an echo?</p>
<p>b) What is the frequency of the sound wave produced by the strike?</p>
<ol>
<li>A solid rectangular platinum bar at 20 degrees C is 600cm x40 cmx 30cm.The resistivity of platinum is 11x10^-8 (horeshoe or something) meter. Find the resistance between the pair of opposing faces (30cm x 40cm).</li>
</ol>
<p>11a. d=rt, keeping in mind that you have to double the .268km b/c it has to go there and come back
b. v=f*wavelength (can't put a lambda in here)</p>