y(t)=h-v0*t-0,5g*t^2; y(t)=0; 30-5*t-5*t^2=0; 6-t-t^2=0; (t+3)*(t-2)=0; t=2;
<span>1.В,2.Б,3.В, </span>
<span>4 дано:</span>
І1=5А
<span>І2=10А</span>
<span>t</span>=0,1<span>c</span>
<em><span>ε</span></em><span /><span>=20</span><span>B</span>
<span> L</span><span>-?</span>
<em><span>ε</span></em><span /><span>=- </span><span>L</span><em><span><span> </span>∆ </span></em><em><span>I</span></em><em><span>∆</span></em><em><span>t</span></em><span>, </span><span><span> </span>L</span><span>=</span><em><span><span>ε</span></span></em><span>*</span><em><span>∆</span></em><span>t/</span><em><span>∆</span></em><span>I</span>
<span>L=20*0,1/10=0,2Гн</span>
<span>5дано:</span>
<span>L=3Гн</span>
<em><span>ε</span></em><span /><span>=</span><span>15</span><span>B</span>
<span>I=50A</span>
<em><span>∆</span></em><span>t-?</span>
<em><span>ε</span></em><span /><span>=- </span><span>L</span><em><span><span> </span>∆ </span></em><em><span>I</span></em><em><span>∆</span></em><em><span>t</span></em><span /><span>, </span><span><span> </span></span><em><span>∆</span></em><span>t=L*</span><em><span>∆</span></em><span>I/</span><em><span> ε</span></em><span /><span>, </span><em><span>∆</span></em><span>t=3*50/15=10c</span>
<span> </span>
Формула mgh, если требуется учесть высоту и земное притяжение, или kx^2/2, если речь идет об упругом теле. x - длина деформации тела, k -коэффициент упругости тела (табличное значение)