.mechanical-energy7{width:179px; height:159px ;}
.mechanical-energy2{width:159px; height:119px ;}
.mechanical-energy3{width:188px; height:91px ;}
.mechanical-energy-conservation1{width:213px; height:146px ;}
.mechanical-energy1{width:172px; height:127px ;}
.mechanical-energy{width:199px; height:134px ;}
.mechanical-energy5{width:192px; height:103px ;}
.mechanical-energy4{width:196px; height:121px ;}