Question

this final exam is cumulative and covers material from the entire course.
instructions
from the list of choices, select the one best answer.
multiple attempts not allowed. this test can only be taken once.
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question 32
a rope is tied to a 0.50 kg box and used to pull a box 2.5 m along a horizontal floor. the rope makes an angle of 42° with the horizontal and has a tension of 10 n. the opposing frictional force between the box and the floor is 1.8 n.
how much work is done by gravity?
zero j
25 j
5.0 j
12 j

Explanation:

Step1: Recall Work Formula

Work is calculated as \( W = Fd\cos\theta \), where \( F \) is force, \( d \) is displacement, and \( \theta \) is the angle between force and displacement.

Step2: Analyze Gravity's Direction

Gravity acts vertically downward (\( F = mg \)). The displacement is horizontal (along the floor). So the angle \( \theta \) between gravity and displacement is \( 90^\circ \).

Step3: Calculate Work Done by Gravity

Using \( W = Fd\cos\theta \), substitute \( \theta = 90^\circ \). Since \( \cos(90^\circ) = 0 \), we get \( W = Fd \times 0 = 0 \, \text{J} \).

Answer:

zero J (the first option)