A little boy rides a roller coaster that makes a loop with a radius of 30.0m. The boy hits the bottom of the loop traveling at 40.0m/s. The net force on the boy is 1350N. What is the mass of the boy? 1800 kg
60 kg
1010 kg
25.3 kg

How many seconds does it take a pebble released from rest off a bridge to fall 29.4 m ? what is the pebble's speed when it has fallen 29.4 m ?

The magnitude of the amount of energy released by burning a fuel source, measured in energy per unit mass, is called its fuel value. note that the fuel value is the negative of the isobaric specific heat of combustion for the fuel. if all the energy obtained from burning 1.23 pounds of butane with a fuel value of 10.85 kcal/g is used to heat 128.0 kg of water at an initial temperature of 18.3 °c, what is the final temperature? note that 1 lb = 453.6 g.

The ability to make things happen is also called a. heat b. force c. matter d. energy