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

Forces and scale diagrams question

Some guidance would be appreciated.

Q) A 2kg mass is hanging by a string from the roof.A horizontal force F is applied to hold the string in the position shown.
The 2kg mass and the string are stationary.

By Drawing a scale diagram or otherwise, find the value of F.

14203486_647755438724716_1651670262_o.jpg
Original post by SuchBants
Some guidance would be appreciated.

Q) A 2kg mass is hanging by a string from the roof.A horizontal force F is applied to hold the string in the position shown.
The 2kg mass and the string are stationary.

By Drawing a scale diagram or otherwise, find the value of F.

14203486_647755438724716_1651670262_o.jpg


Draw a vector triangle, the vertical weight force W is 2g Newtons

it'll look something like this
Capture.PNG

since it's a right angle triangle you could solve it using trig (recalling sohcahtoa)
Reply 2
Avatar for Jpw1097
Jpw1097
19
Original post by SuchBants
Some guidance would be appreciated.

Q) A 2kg mass is hanging by a string from the roof.A horizontal force F is applied to hold the string in the position shown.
The 2kg mass and the string are stationary.

By Drawing a scale diagram or otherwise, find the value of F.

14203486_647755438724716_1651670262_o.jpg


If you didn't want to draw a triangle, you could always resolve the forces. Since the mass is in static equilibrium, the vertical component of tension must be equal (and opposite) to weight. Hence Tcos30*°=2g.

The horizontal component of tension must be equal to F. Therefore, F=Tsin30°.

You can find T using the first equation and then you can use this value of T in the second equation to find F.

Although you can simply draw a right-angled triangle in this case, that may not always be the case.

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you