0

Guest

Courses New

The force f1 parallel to incline plane that is necessary to move a body up the inclined is double the force f2 to that is necessary to just prevent them sliding down them

The force f1 parallel to incline plane that is necessary to move a body up the inclined is double the force f2 to that is necessary to just prevent them sliding down them

Question Image
Grade:11

3 Answers

Kruthik
119 Points
6 years ago
Let’s consider the 2nd case. F2 is the force required just to prevent the body from sliding. Now, if we consider the FBD, there will be F2 the direction opposite to wsinθ(component of weight along the incline). The friction force will act in the direction opposite to wsinθ, as the body tends to move down the incline, and F2 prevents it.
Thus, we get F2=wsinθ-fr (fr = frictional force)———— 1
As ? is the angle of repose, μ = tan?....2
From 1, F2=wsinθ - μwcosθ (fr = μN, and N is the normal reaction, component for weight perpendicular to the incline)
So, F2=wsinθ – tan?cosθ
Put tan?=sin?/cos?
Thus,F2=wsinθ – (sin?cosθ)/cos?
On further solving, we get F2 = wsin(θ - ?)sec?, that is option ‘A’ which is the answer.
Hope this helped you. Good Luck.
Kruthik
119 Points
6 years ago
Let’s consider the 2nd case. F2 is the force required just to prevent the body from sliding.
Now, if we consider the FBD, there will be F2 the direction opposite to wsinθ(component of weight along the incline). The friction force will act in the direction opposite to wsinθ, as the body tends to move down the incline, and F2 prevents it.
Thus, we get F2=wsinθ-fr (fr = frictional force)———— 1
As ? is the angle of repose, μ = tan?....2
From 1, F2=wsinθ - μwcosθ (fr = μN, and N is the normal reaction, component for weight perpendicular to the incline)
So, F2 = wsinθ – wtan?cosθ
Put tan? = sin?/cos?
Thus,F2 = wsinθ – w(sin?cosθ)/cos?
On further solving, we get F2 = wsin(θ - ?)sec?, that is option ‘A’ which is the answer.
Hope this helped you. Good Luck.
Kruthik
119 Points
6 years ago
Sorry, but the first solution had some minute errors, so I reanswered... The second answer is correct.

Think You Can Provide A Better Answer ?

Other Related Questions on Mechanics

View all Questions ยป

ASK QUESTION

Get your questions answered by the expert for free

Answer and earn gift vouchers

Win Gift vouchers upto Rs 500/-

View courses by askIITians

Design classes One-on-One in your own way with Top IITians/Medical Professionals

Click Here Know More

Complete Self Study Package designed by Industry Leading Experts

Click Here Know More

Live 1-1 coding classes to unleash the Creator in your Child

Click Here Know More

a Complete All-in-One Study package Fully Loaded inside a Tablet!

Click Here Know More