0

HETAV PATEL

Grade 11,

Courses New

A block of mass 0.5 kg rests on the 8nclined surface of a wedge of 2 kg. The wedge is acted on by a horizontal force F and slides on a frictionless surface . If the coefficient of static friction between the wedge and the block is 0 8 and the angle of inclination is 37° , maximum value of F for which the block doesn't slip is approximately ________ ?

A block of mass 0.5 kg rests on the 8nclined surface of a wedge of 2 kg.  The wedge is acted on by a horizontal force F and slides on a frictionless surface . If the coefficient of static friction between the wedge and the block is 0 8 and the angle of inclination is 37° , maximum value of F for which the block doesn't slip is approximately ________ ?

Grade:11

1 Answers

Arun
25750 Points
5 years ago
Fn - mgcos = 0" 

Not this time. The normal rules don't apply. The whole system is accelerating. The direction of the y axis you're using in that equation isn't "up". Find the component of a that's in the direction of your y axis. That's a sin theta. 

Fn - mg cos theta = ma sin theta 

"-mgsin + ff = m2a (x)" 

I guess you realized something was fishy at this point, since you wrote "(x)". Problem is, after you wrote it, you ignored it. Same deal as above. Find the component of a that's in the direction of your x axis. 

-mg sin theta + ff = -ma cos theta 

Note the minus sign on the right because I'm assuming acceleration is opposite the direction of your x axis. It doesn't matter if I'm wrong - you will get a negative result for a, and just switch it. Solve for a, then you can easily using eqn. 1 to find the force. 

Also, now you need to find the maximum and minimum values for F, so also write 

-mg sin theta - ff = -ma cos theta 

And solve again. In this case the friction is actually keeping the block from sliding up the wedge, like dishes on a table when you pull the tablecloth out. 

I think the kg is just a mistake in the book. The correct answer should be 

Think You Can Provide A Better Answer ?

Other Related Questions on Mechanics

View all Questions »

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