.gravitational-potential-energy1{width:159px; height:164px ;}
.gravitational-potential-energ-example1{width:44px; height:110px ;}
.gravitational-potential-energ-example1b{width:141px; height:91px ;}
.gravitational-potential-energ-example4{width:150px; height:72px ;}
.gravitational-potential-energ-example3{width:144px; height:130px ;}
.gravitational-potential-energ-example3b{width:210px; height:112px ;}
.gravitational-potential-energ-example2{width:77px; height:176px ;}
.gravitational-potential-energ-example2b{width:177px; height:180px ;}