please help physics paper 3

[vivi2003]

hey guys, i'm a newbie here
please help me to solve this question

http://www.xtremepapers.me/CIE/Cambridge IGCSE/0625 - Physics/0625_w05_qp_3.pdf
number 2c, i don't understand this question eventho i have read the ms
thank you !

 

[ChrisChin]

The pivot exerts a force on the meter rule. You're asked to describe that force in terms of magnitude and direction.

correction:

total upward force = 8.0N
total downward force = 6.0N + 1.5N + pivotal force

Because system is in equilibrium, total upward force = total downward force.

.: pivotal force = 0.5N

Direction is downwards because it is positive in the downwards direction.

If you want to do it the A-Level way, it's:

Take all upwards forces as -ve;

.: sum of vertical forces = -8.0 + 6.0 + 1.5 + pivotal force = 0 (net force in any direction is 0 for system in equilibrium)

.: pivotal force = 8.0 - 6.0 -1.5 = 0.5N

 

[HorsePower]

but, how does the pivot exert a down ward force. shouldnt it be upward.

 

[xIshtar]

The markscheme says 0.5N

 

[ChrisChin]

Sorry, I corrected it.