Arock is suspended by a light string. when the rock is in air, the tension in the string is 42.2 n . when the rock is totally immersed in water, the tension is 30.6 n . when the rock is totally immersed in an unknown liquid, the tension is 21.0 n . what is the density of the unknown liquid?

Aperson gives a shopping cart an initial push along a horizontal floor to get it moving, and then lets go. the cart travels forward along the floor, gradually slowing as it moves. consider the horizontal force(s) on the cart while it is moving forward and slowing. which of the following statements is correct? (a) both a forward and a backward force are acting on the cart, but the forward force is larger. (b) only a forward force is acting which diminishes with time. (c) both a forward and a backward force are acting on the cart, but the backward force is larger. (d) only a backward force is acting, no forward force.