# need some help in Alevel maths

• Mar 31st 2008, 05:08 AM
need some help in Alevel maths
hey everyone i have attached the problems (Yes) i will try to see what how u guys can solve them and later i will ask questions thanks a lot.
• Mar 31st 2008, 11:38 PM
CaptainBlack
Quote:

hey everyone i have attached the problems (Yes) i will try to see what how u guys can solve them and later i will ask questions thanks a lot.

4a). The two reaction forces are equal (you are told so) and as the plank is
statric their sum must equal the total load which is (60+90)g Newtons, so
the reaction of the plank at B is 75g N.

RonL
• Mar 31st 2008, 11:43 PM
CaptainBlack
Quote:

Let $x$ be the distance of the centre of mass of the plank from A. Then
$2 \times 60 \times g + x \times 90 \times g - 6 \times R_B=0$
where $R_B$ is the reaction at B found in the first part of this question.