The boy at D has a mass of 50 kg, a center of mass at G, and stands on a plank at the position shown. The plank is pin-supported at A and rests on a post at B. Neglecting the weight of the plank and post, determine the magnitude of force P his friend (?) at E must exert in order to pull out the post. Take _{B} = 0.3 and _{C} = 0.8.

[A].

P = 360 N

[B].

P = 264 N

[C].

P = 229 N

[D].

P = 293 N

Answer: Option B

Explanation:

No answer description available for this question.

Then take sammetion of fx & sammetion of fy equal to zero and find moment with respect to point a. Also apply work energy principle for bettting third equation.

Vignesh said:
(Mar 28, 2012)

Here should we take planck and post as two bodies and draw the free body diagrams for each of them? please explain the procedure!

Rohan said:
(Apr 9, 2012)

Draw fbd of the diagram then calculate summation of x and why separately also take moment at point a.

Nasma Noor N V said:
(Mar 26, 2014)

I am getting two different answers if we take first fbd of plank and then post. If we take moment about the base for post am getting 264N. If I take sum of forces in x and why direction am getting 284. 1.

Alfredo said:
(May 25, 2015)

I need more explanation to your solution thank you and regard.

Lira said:
(Jun 1, 2015)

I still don't understand how do you get into the answer?

Hasan said:
(Jun 4, 2015)

I want the details of solution?

Madara said:
(Apr 12, 2016)

Explain the solving method of this question.

Sumit Manna said:
(Jul 23, 2016)

Force create at A=50g/3 and force in B = 100g/3 verticaly both Friction force is 0.3 * 100g/3 at B.
Moment about C : 0.3 * 100g/3 * (0.3 + 0.4) = Fcos30 * 0.3.

So F= 264N.

James Oketch said:
(Feb 13, 2017)

Not able to reach the answer. Please explain me in detail.

Debolina said:
(Aug 26, 2017)

Please solve it clearly.

Goku said:
(Nov 27, 2017)

Please explain about C @Sumit Manna.

Shree said:
(Oct 23, 2018)

Please explain in detail @Sumit manna.

Ajay Kumar said:
(May 13, 2019)

How? Please explain the answer.

Ajay Kumar said:
(May 13, 2019)

Please solve it.

Chethan said:
(Jul 4, 2020)

Take vertical forces equal to zero, Ay + Ny = 490.5.
Take moment at A, then Ny*3=mg*2, By solving we get N=327.
Friction force = static friction coefficient * normal force.
f = 0.3 * 327 = 98.1;
Now take moment at c(post bottom),we get f(0.3+0.4) = Fcos30 * 0.3
By solving the above equation we get F = 264.115 Newtons.

Post your comments here:

Name *:

Email : (optional)

» Your comments will be displayed only after manual approval.