# mechanics 1 question

By overtoom

@overtoom (33)

United States

June 19, 2011 4:13pm CST

an object of masss 8kg slides down a line of greatest slope of sn inclined plane . its initial speed at the top of the plane is 3m/s and its speed at the bottom of the plane is 8m/s . the work done against the resistance to motion of the object is 120j . find the height of the top of the plane above the level of the bottom ?
please help me with that , i'm kinda sucking hard !!!!!!

2 responses

@alamsher007 (714)

• Australia

21 Jun 11

Loss in G.P.E= Gain in kinetic energy + reistance to motion
8x10xh = .5x8x(8^2-3^2)+120
h = (.5x8x(8^2-3^2)+120)/8x10
solve it using a calculator and you will get you answer.

@josephperera (2906)

• Sri Lanka

23 Jan 12

We were doing these sums in Grade 8 and cannot remember much now. But this is an answer calculated from a standard and common formula. For instance I never forget formulas like V^2=u^2+2fs, where V is the final speed, u is the initial speed, f is the gain in velocity, and s is the distance.
When there is an incline you have to use Tan, Cos and Sine to see the relative vertical distance of the inclined fall.