AL physics ~ Projectile motion ~~

2008-10-27 2:12 am
A projectile leaves the ground at an angle of 60 to the horizontal. Its initial kinetic energy is E.
Neglecting air resistance, find its KE at the highest point of the motion in terms of E.

The answer is E/4

Can anyone show me the step??

回答 (2)

2008-10-28 3:04 am
✔ 最佳答案
Let v be the initial speed of the projectile.

As the horizontal motion is uniform, the horizontal speed

= vcos60* = v/2

Initially, K.E. = 1/2 mv2 = E

At the highest point, the projectile has only the horizontal component of the speed, which is equal to v/2

K.E. at the highest point

= 1/2 m(v/2)2

= 1/4 (1/2 mv2)

= E/4

參考: Myself~~~
2008-10-28 4:53 am
您信我用這方法可以幫助您解決身體問題, 碧咸球隊都是用它.
你係咪想型d, fit d又健康d?
我個女13歲, 都是用這方法, 一個月減10磅, 三個月減20磅.
改善鼻敏感, 流鼻血, 靚咗, FIT咗, 讀書仲好咗, 仲拿第一添.
我做文職, 133磅, 160CM , 用咗簡單又健康既方法!
我用左4個月減左20磅, 改善頭痛,胃痛, 暈車浪,植物曲脹, 越來越fit!面色仲好過以前!
網站可以增肥, 減肥, 改善身形, 健康, 體重控制,
美容護膚, http://www.healthcometrue.com/life
[[有營養顧問免費跟進^^ ]]
TEL: 93227176 阿紅


收錄日期: 2021-04-19 02:09:50
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20081026000051KK01859

檢視 Wayback Machine 備份