You throw a baseball (mass 0.145 kg) vertically upward. It leaves your hand moving at 12.0 m/s. Air resistance can be neglected. A. At what height above your hand does the ball have half as much upward velocity?
B. At what height above your hand does the ball have half as much kinetic energy as when it left your hand?

Explanation:

A ) initial velocity u = 12 m /s

final velocity v = 6 m /s

height = h

acceleration = - g = - 9.8 m /s²

v² = u² - 2gh

6² = 12² - 2 x 9.8 x h

h = 5.51 m

B )

Let the final velocity when energy becomes half be V at height H

kinetic energy at height h = 1/2 m V²

Given ,

.5 x 1 / 2 m x 12² = 1/2 m x V²

V² = 12² / 2

V = 8.486 m /s

V² = u² - 2 gH

8.486² = 12² - 2 x 9.8 x H

H = 3.67 m .  

the answer is ampere

the ampere is used to measure electricity. an ampere is a unit of electric current equal. a unit of measure for the flow of current in a circuit. one ampere is the amount of current flow provided when one volt of electrical pressure is applied against one ohm of 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