7. what is the force of air resistance on an
2.02 80-kg sky diver who is falling downward
with an acceleration of 4.0 m/s ?
a 320 n
b 392 n
( 464 n
d. 784 n

C) 464 N

Explanation:

The equation of the forces acting on the skydiver is:

where

(mg) is the weight of the skydiver, acting downward, with

m being the mass of the skydiver

g is the acceleration of gravity

R is the air resistance, acting upward

a is the acceleration of the skydiver

In this problem:

m = 80 kg

g = 9.8 m/s^2

a = 4.0 m/s^2

Solving the equation for R, we find the force of air resistance:

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form

gravitational energy

electrical energy

kinetic energy

ligh energy