A box is lifted with a pry bar, by slipping the bar under the box and lifting up on the bar. If the pry bar is 2m in length and it is grasped at the end, and the box is located at the opposite end, the fulcrum, with its center of gravity at a distance of 0.5 m from the fulcrum.

what is the size of the force required to lift the box if the box has a weight of 100N?

.5*100=1.5* F solve for force F

I THOUGHT IT WAS .5X100=50/2=25N

To find the force required to lift the box using a pry bar, we can use the principle of moments. The principle of moments states that the total moment acting on an object is equal to the sum of the moments of all the forces acting on it.

In this case, we can consider the moments of the weight of the box and the force applied at the end of the pry bar.

The moment of a force is calculated by multiplying the magnitude of the force by the perpendicular distance from the line of action of the force to the point of rotation (fulcrum).

First, let's calculate the moment caused by the weight of the box. The weight of the box is acting downward and its magnitude is 100 N. The center of gravity is located at a distance of 0.5 m from the fulcrum. Therefore, the moment caused by the weight of the box is:

Moment of weight = Weight x Distance from the fulcrum
= 100 N x 0.5 m
= 50 Nm

Next, let's calculate the moment caused by the force applied at the end of the pry bar. The force at the end of the pry bar is acting upward to lift the box. We need to find the magnitude of this force.

The principle of moments states that for an object in equilibrium, the sum of the clockwise moments is equal to the sum of the anticlockwise moments. In this case, we have only one anticlockwise moment caused by the weight of the box.

Since the box is in equilibrium, the moment caused by the force applied at the end of the pry bar must be equal to the moment caused by the weight of the box. Therefore, we have:

Moment of force = Moment of weight
Force x Length of the pry bar = Weight x Distance from the fulcrum

Rearranging the equation to solve for the force:

Force = (Weight x Distance from the fulcrum) / Length of the pry bar
= (100 N x 0.5 m) / 2 m
= 25 N

Therefore, the force required to lift the box using the pry bar is 25 N.