After James Chadwick discovered the neutron, atomic theory expanded to include isotopes. Isotopes have many practical uses. For example, scientists use the relative amount of carbon-12 to carbon-14 in ancient bones to determine how old they are. How many neutrons are in an atom of Carbon-147 A 2 B 6 C 8 D 14

You are your friend move a new refrigerator into his kitchen. you apply a horizontal force of 252 n in the negative x direction to try and move the 56 kg refrigerator. the coefficient of static friction is 0.61. (a) how much static frictional force does the floor exert on the refrigerator? give both magnitude (in n) and direction. magnitude n direction (b) what maximum force (in n) do you need to apply before the refrigerator starts to move?