(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A 45 degree wedge is pushed along a table with constant acceleration A. A block of mass m slides without friction on the wedge. Find its acceleration (gravity is downwards),

2. Relevant equations

3. The attempt at a solution

I answered the above question on another forum, but got the wrong answer, apparently. Here's my working. Where did I go worng?

Suppose that the wedge is stationary. Then the accelerating force, down the slope, is mgsin45. So the acceleration of the small mass, down the slope, is gsin45.

If the wedge is now moving with a (constant) accln of A, then that accln can be added vectorially to the "static" accln of the small mass.

http://img223.imageshack.us/img223/1896/wedge1ub9.th.jpg [Broken]

a is the resultant accln of the two component acclns, and (vectorially),a=A+gsin45.

Your question isn't clear in which direction the force is acting wrt to the orientation of the wedge. The force could be in the same direction as the wedge is pointing, or in the opposite direction, in which case the vector diagram is like this,

http://img223.imageshack.us/img223/299/wedge2pc6.th.jpg [Broken]

If you wish to evaluate the accln, then use the cosine rule.

a² = A² + (gsin45)² - 2A.gsin45.cos(45 or 135)

Now, the OP told me that if A = 3g, then the answer is g. But I can't see how that answer is got. Can someone explain

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# Homework Help: Mass on accelerating wedge

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