The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

components of forces help.

how do i approach this question?

physicsismental.jpg
Reply 1
Avatar for soup
soup
11
Are you familiar with the dot product? If so, the component of force in a direction is the force dotted with the unit vector in that direction. And since the force and direction are at right angles...
Reply 2
Avatar for cmad95
cmad95
2
all the forces given from a up parrallel to the hill on the block.


so Because F = MA

since there is no mention of whether it is moving IE is there a friction force we are going to assume that F is not acting. So

F = -Wcos(theta)

notice that when this happens there is no component of R that makes up the total force when resolved parrellel to the hill. this is because R is perpendicular to the direction in which you resolved the forces
Reply 3
Avatar for CoolRunner
CoolRunner
OP
9
Original post by soup
Are you familiar with the dot product? If so, the component of force in a direction is the force dotted with the unit vector in that direction. And since the force and direction are at right angles...


Ah i get it now, When resolving the component parallel is the horizontal (RCos(theta)) since the force and direction of R = 90 degrees, therefore RCos(90) = 0.

thanks soup :biggrin:
Reply 4
Avatar for krisshP
krisshP
14
Original post by CoolRunner
Ah i get it now, When resolving the component parallel is the horizontal (RCos(theta)) since the force and direction of R = 90 degrees, therefore RCos(90) = 0.

thanks soup :biggrin:


Even if you just tilt your head a bit or the diagram, you should straight away notice how R is a straight perpendicular vertical line to the inclined surface. So it cannot have any horizontal component parallel to the inclined surface.

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you