<span>По закону сохранения энергии:
kx</span>²<span>/2=mgh, откуда
k=2mgh/x</span>²
<span>k=2*0,01*10*0,2/0,01</span>²<span>=400.</span>
Дано:
<span>t1=18’C</span>
<span>t2=26’C</span>
<span>m=200г=0,2кг</span>
<em><span>∆</span></em><span>U=608Дж</span>
<span>с-?</span>
<em><span>∆</span></em><span>U</span><span>=Q, Q=c</span><em><span>m∆</span></em><span>t</span>
<span>c=Q/m</span><em><span>∆</span></em><span>t, </span><em><span>∆</span></em><span> </span><span>t=t2-t1,</span><em><span> <span> </span>∆</span></em><span>t=26-18=8’C</span>
<span>c=608/0,2*8=380Дж</span><span>/</span><span>кгК</span>