A body of mass 40kg is being dragged along the floor by a rope inclined at 60 degrees to the horizontal. The frictional force between the box and the floor ...

Assessment: JAMB UTME - Physics - 1995 Subject: Physics

Question 1 Report

A body of mass 40kg is being dragged along the floor by a rope inclined at 60 degrees to the horizontal. The frictional force between the box and the floor is 100N and the tension on the rope is 300N. How much work is done by dragging the box for a distance of 4m

Answer Details
The work done in this situation can be calculated using the formula: Work = Force x Distance x cos(theta) where force is the net force acting on the object, distance is the distance traveled by the object, and theta is the angle between the direction of the force and the direction of motion. First, we need to calculate the net force acting on the object. We can do this by resolving the forces acting on the object along the horizontal and vertical directions. The vertical component of the tension force is equal to Tsin(60), which is equal to 300 x 0.5 = 150 N. The weight of the object is equal to mg, which is equal to 40 x 9.8 = 392 N. Since the object is not moving vertically, the vertical component of the net force acting on the object is zero. The horizontal component of the tension force is equal to Tcos(60), which is equal to 300 x 0.5 = 150 N. The frictional force acting on the object is equal to 100 N. Therefore, the net force acting on the object along the horizontal direction is equal to: Fnet = Tcos(60) - frictional force = 150 - 100 = 50 N Now we can calculate the work done by using the formula: Work = Force x Distance x cos(theta) = Fnet x distance x cos(0) = 50 x 4 x 1 = 200 J Therefore, the work done by dragging the box for a distance of 4m is 200J. The correct option is (C) 200J.

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