Question

You are carrying a 7.0-kg bag of groceries as you walk at constant velocity along the sidewalk. You walk a distance of 82 meters and hold the bag at a height of 1.5 m above the sidewalk. How much work against gravity do you do on the bag?
100 J

0 J

5600 J

82 J

Answer 1

Answer:

0J

Option: B

Explanation:

Work is done when something is moved by the force in the direction of the force. That is the force (e.g., the weight) and the direction the object moves must be aligned for work to be done. In this given condition, the direction is horizontal and the force is downward as its gravity force. That 90° between the two vectors.

The work function is W = m × g ×h × cosθ

$\text { Where, in this case theta }=90^{\circ}$

Hence,  

Work done = 7 × 9.8 × 1.5 × cos(90)  

Work done = 0 (cos$90^{\circ}$ = 0)

Work done = 0

Therefore work done is 0 J.