Question

An inclined plane is used to raise a 100 kg box to a height of 5 m. How long must the inclined plane be if a force of 250 N is used to push the box up the inclined plane?

Answer 1

Answer on Question #48989, Physics, Mechanics | Kinematics | Dynamics

Let us use Work-Energy theorem in order to find the length of the inclined plane. Initially, body had to potential energy, but after being raised it attained energy $U = mgh$ , where $h$ is the height above the ground. The change in energy is equal to the work done to move the box $s$ meters, which is the length of the plane. Hence, $mgh - 0 = F\cdot s$ , from where

$$s = \frac {m g h}{F} = \frac {1 0 0 k g \cdot 9 . 8 1 \frac {m}{s ^ {2}} \cdot 5 m}{2 5 0 N} = 1 9. 6 2 m.$$