Your cell phone is sitting on your desk, what kind of force is your desk exerting on your cell phone?

a force making it turn around and go to your hand

or as school says, an upwards force balancing out the force of gravity making it reach a state of equilibrium. I wasn't taught what that was called, but know it is an upwards force countering gravity so that your cell phone is in a balance state, and gravity isn't pulling it to the center of the earth.

Explanation:

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s

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