Question

calculating net force
which object has a net force of -68 n?
f = -53 n
f = 31 n
f = 53 n
f = -74 n
f = 89 n
f = -89 n
f = 103 n
f = -56 n
f = 27 n
f = -102 n
f = -27 n
f = 34 n

Explanation:

Step1: Analyze the first object

For the first object, we have forces in different directions. Let's assume the vertical (or one axis) forces: \( F_f = -53\,\text{N} \), \( F_p = 53\,\text{N} \) (these two cancel out: \( -53 + 53 = 0 \)). Horizontal (other axis) forces: \( F_N = 31\,\text{N} \), \( F_q = -74\,\text{N} \). Net force: \( 31 + (-74) = -43\,\text{N} \).

Step2: Analyze the second object

Vertical forces: \( F_f = -56\,\text{N} \), \( F_p = 103\,\text{N} \). Horizontal forces: \( F_N = 89\,\text{N} \), \( F_q = -89\,\text{N} \) (these two cancel out: \( 89 + (-89) = 0 \)). Net force: \( -56 + 103 = 47\,\text{N} \). Wait, no, maybe axes are different. Wait, maybe each object has two pairs of forces (like x and y, but maybe in two directions, each with two forces). Wait, re - examining: For the second object, let's consider the two directions. Let's say one direction has \( F_f=-56\,\text{N} \) and \( F_p = 103\,\text{N} \), the other has \( F_N = 89\,\text{N} \) and \( F_q=-89\,\text{N} \) (the \( F_N \) and \( F_q \) cancel). So net force from the first pair: \( -56 + 103=47\,\text{N} \). No, that's not - 68. Wait, maybe I misassigned axes. Let's look at the third object.

Step3: Analyze the third object

Forces: \( F_f=-102\,\text{N} \), \( F_p = 34\,\text{N} \) (one direction), \( F_N = 27\,\text{N} \), \( F_q=-27\,\text{N} \) (the \( F_N \) and \( F_q \) cancel: \( 27+(-27) = 0 \)). Net force from the other pair: \( -102 + 34=-68\,\text{N} \). Yes! Let's check again. The third object: forces in one direction (say y - axis): \( F_N = 27\,\text{N} \), \( F_q=-27\,\text{N} \), sum is \( 27+( - 27)=0 \). Forces in the other direction (x - axis): \( F_f=-102\,\text{N} \), \( F_p = 34\,\text{N} \), sum is \( - 102 + 34=-68\,\text{N} \). So the net force is - 68 N for the third object (the one with \( F_f=-102\,\text{N} \), \( F_p = 34\,\text{N} \), \( F_N = 27\,\text{N} \), \( F_q=-27\,\text{N} \)).

Answer:

The object with forces \( F_f=-102\,\text{N} \), \( F_p = 34\,\text{N} \), \( F_N = 27\,\text{N} \), \( F_q=-27\,\text{N} \) (the third diagram) has a net force of - 68 N.