Mechanical Engineering - Engineering Mechanics - Discussion

Discussion Forum : Engineering Mechanics - Section 1 (Q.No. 20)
20.

The above figure shows the two equal forces at right angles acting at a point. The value of force R acting along their bisector and in opposite direction is
P/2
2P
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
18 comments Page 1 of 2.

Ankit Virus said:   1 year ago
R = Pcos45 + Psin45.
R = P(cos45 + sin45).
R = P(1/√2+1/√2) {from value cos45 and sin45=1/√2},
R = P(2/√2).
R = P√2.

Hence R = √2P.
(4)

Philip said:   3 years ago
R*2 = P*2 + P*2 using Pythagoras theorem.

Let's make square root of both sides just to remove square from R.
R*((2)*(1/2)) = (P*2 + P*2)*(1/2).
R*(2/2) = (2P*2)*(1/2),
R = 2P*(2/2),
R = 2P.
(2)

Kesav said:   4 years ago
Lamis theorem R/ sin 90 = P/sin 135.
i. e. R= √2 P.
(2)

Deepak Kumar said:   7 years ago
Lami's theorem can be used only coplanar forces.
(1)

Nayeem said:   7 years ago
This problem is about non coplanar forces. Why is everyone using parallelogram law of coplanar forces?
(1)

Arshad said:   8 years ago
R^2 = P^2 + P^2 + 2P^2cos90 =>
R^2 = 2P^2 + 0 =>
R = √2P.
(4)

Dileep valli kumar said:   9 years ago
R=√(p2+p2+ 2ppcos90).
Cos90 = 0.

ThenR = √[p2+p2].
R = √[2p2),
R = (√2)(p).
(1)

Esakkiyappan said:   9 years ago
Law of a parallelogram.

We know that Resultant force R =Square of (P^2 + Q^2 +2PQcosangle value).
Here in the problem, The above figure shows the two equal forces at right angles acting at a point.
so angle value is 90 Degrees
R = Square of (P^2 + Q^2 + 2PQcos90), P = Q.
therefore R =Square of (P^2 + P^2 + 2P * P * 0).
R = Square of (2P^2 + 0).
R = Square of (2) * P.

Option C.
(2)

Naveen said:   10 years ago
I did not understand this problem please help.
(2)

BINIT RANJAN said:   10 years ago
Use Lami's theorem to get the answer in easy way, angle between two equal forces is 90 and that of bisector and any of two force is 135.


Post your comments here:

Your comments will be displayed after verification.