A 3 meter tall 40 degree inclined plane with a coefficient of friction of .3 with a box sliding from its top has this acceleration and final velocity.

Answer 1

Initial PE= mg*3
frictionwork:mg*mu*Cos40*3/sin40

intialPE-workdonebyfriction=finalKE

Answer 2

two pint charges are 4 cm apart. They are moved to a new distance of 2 cm. By what factor does the resulting mutual forces between them change.

a. 1/2
b. 2
c. 1/4
d. 4