# Friction On A BlockWatch

#1
A block of wood of mass 5kg rests on a table. A force of magnitude 35N acting upwards at an angle of x to horizontal is applied to the block but the block does not move. Given that the normal contact force between block and the table has magnitude 30N, find x and the friction.

I got x = 34.8° and F = 28.7N but it is apparently wrong.
Last edited by esrever; 1 month ago
0
1 month ago
#2
Method is probably alright
Maybe you're using g=10.0 when you should be using g=9.8 ?

if so you'd get ECF marks in an exam
1
#3
(Original post by Joinedup)
Method is probably alright
Maybe you're using g=10.0 when you should be using g=9.8 ?

if so you'd get ECF marks in an exam
I am using g = 10 but it is specified by my exam board. My textbook states that the answer is x = 25.4°, friction F = 31.6N.
0
1 month ago
#4
I get the exact same answers as you, using g=10.

Guessing the textbook only gives answers, not solutions?
Out of interest, is your textbook wrong on other occasions or is it usually correct?
Assuming their answer is correct, I can't see where they'd get those answers from.

The maths forum would be a good place to post this question, you'd get more responses there.
It's physics, yes, but could also easily fall under the mechanics section in maths so posting in that forum would be a safer bet.
0
#5
(Original post by JaredzzC)
I get the exact same answers as you, using g=10.

Guessing the textbook only gives answers, not solutions?
Out of interest, is your textbook wrong on other occasions or is it usually correct?
Assuming their answer is correct, I can't see where they'd get those answers from.

The maths forum would be a good place to post this question, you'd get more responses there.
It's physics, yes, but could also easily fall under the mechanics section in maths so posting in that forum would be a safer bet.
Thank you for your response . The textbook is occasionally wrong so I guess the textbook was indeed wrong here.
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