Astudent wanted to know what would happen in the swinger experiment if he changed the way he made the pendulum. instead of using string he used fishing line to make his pendulum the standard 38 cm long. he used a washer at the end for the pendulum bob. then he counted how many times his pendulum swung back and forth in 15 seconds. do you think he has done a good job of controlling the variables?

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.