Maths問題請教 , 各位知識朋友 , 入黎幫我手 ar !!!

[匿名]

2008-07-17 2:15 am

教下我,唔識做啊><要有步驟.thankyou!

1.Equations of uniformly accelerated motion in straight line mainly deal with the following five variables:
t = time; u = initial velocity at t = 0; v = final velocity at time t; a = acceleration (assumed constant at this moment); and s = displacement between t = 0 to time t.
a)Sketch and label the velocity-time (v-t) graph using the above variables when applicable;
b)Prove with the aid of your sketch that s = ut + 1/2 at^2 ;
c)Prove with the aid of your sketch that v^2 = u^2 + 2as ;
d)Prove with the aid of your sketch that v = u + at ; and
e)An object is thrown vertically upwards with a velocity of 10 m/s. Determine the maximum height it reaches and the time taken for it to reach that height.

回答 (1)

So Much

2008-07-18 3:33 am

✔ 最佳答案

d)Prove with the aid of your sketch that v = u + at

Ans:
as we all know,
a=(v-u)/t
at=v-u
v=u+at//

b)Prove with the aid of your sketch that s = ut + 1/2 at^2

sub v = u + at into v^2 = u^2 + 2as

(u+at)^2=u^2+2as
u^2+2uat+a^2 t^2=u^2+2as
2uat+a^2 t^2-u^2=2as
s=ut+(1/2)at^2//

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