In order to have a contact force acting on an object, the force
a. must be positive
b. must be negative
c. must be touching the object
d. cannot be touching the object

Idon’t understand this page, can someone ?

Main expenses you plan on making payments on a new car too. you want to spend 15% of your monthly net pay on the car payment, insurance, registration, and taxes combined. what is your monthly car allowance? $149.46 $298.91 $448.37 $597.83

Which sentence about particles in matter is true? a. atoms are present in solids and liquids but not in gases. b. the particles of matter are in constant motion. c. the same kinds of atoms are found in different elements. d. when a solid changes to a liquid, the sizes of the particles change.