00:01
All right, so let's say an object is pushed up a slope that's inclined at 30 degrees, and this object has a mass of 1 .25 kilograms.
00:13
It has an initial velocity, we'll call v of 4 .45 meters a second, and when it comes in contact with the spring, it compresses it a distance of 0 .35 meters, and that's after traveling a distance s of 1 meter along the surface, and finally, the coefficient of kinetic friction is 0 .25.
00:34
So we want to use this information to find the spring constant of the spring.
00:38
So the kinetic energy the block has, when it comes into contact with the spring, is going to be the initial kinetic energy plus the work done by gravity, which will actually be negative, plus the work done by friction.
00:54
And so if we solve for this, this is, of course, one -half mv squared minus mgs, sine theta, and then minus mu k m gs cosine theta.
01:08
So if we compute with that is, there's about 3 .6 joules...