A bulldozer exerts 1000 pounds of force to prevent a 5000 pound boulder from rolling downa hill. Determine the angle of inclination of the hill.
The boulder is exerting a 5000 pound force downward, which can be broken into a component parallel to the hill (1000 pounds), and a force normal to the hill. If the angle of inclination of the hill was zero, the force would be all normal. If the angle of inclination was 90 degrees, the force would be all parallel. The majority of the force is normal to the hill, a clue that the angle is less than 45 degrees. If you diagram the forces on the boulder, you can see that the parallel force is the total force times the sine of the angle of incline. 1000 = 5000sinA (solution left for student)
