JUNE TOB SSCE PHYSICS 2 THE (a) Explain with the aid of a diagram what is meant by the moment of a torce about a point. (b) State the conditions of equilibrium for a number of coplanar par- alielforces. A metre rule is found to balance at the 48cm mark. When a body of mass 60g is suspended at the Bom mark, the balance point is found to be at the 30cm matk Calculate the mass of the metre Tule () the distance of the balance point from the zero end, I the body was moved to the 13cm mark. (c) Show that the efficiency E. the force ratio MA. and the velocity ratio VR of a machine are related by the equation MA * 100% VA

Answer8.0m;

195, i took the test already.

This is actually a calculus question. so, basically, this is a related rates question where you are given 1 quantity and you have to find the other.  we'll define some variables first.x = 9 ftdx/dt = 7 ft/secl = 15 ftsince you want to find the area, you have to find a formula for it. which is: we know the base (x), but we don't know the height (h). we can figure it out by solving for it. we have to form an equation which we can figure out height from given the information we have. this equation is: plug in known values: solve for h: now, let's solve for the rate at which h is changing. we can do so by differentiating the pythagorean theorem (above). let's do that: plug in values: now we have all the given information to do this problem. so, to figure out the rate of change of area, we can differentiate (with respect to time) the earlier equation: which is equal to: plug in known values: so, the area of the triangle is changing at approximately 18.375ft²/sechope this all makes sense. if it doesn't, either contact me, or watch khan academy - he explains it real well. special credit to turtaniumx and quietself for letting me know of the error, and fix it!