Question

1. four forces act concurrently on a block on a horizontal surface as shown in the diagram below. as a result of these forces, the block (1) moves at constant speed to the right (2) moves at constant speed to the left (3) accelerates to the right (4) accelerates to the left

Explanation:

Step1: Analyze vertical forces

The vertical forces are \(80N\) upward and \(80N\) downward.

$$F_{y - net}=80N - 80N=0N$$

Step2: Analyze horizontal forces

The horizontal forces are \(120N\) to the left (negative direction) and \(100N\) to the right (positive direction).

$$F_{x - net}=100N-120N=- 20N$$

According to Newton's second law \(F = ma\). Since \(F_{x - net}
eq0\), there is a non - zero acceleration. The negative sign in \(F_{x - net}=-20N\) indicates the direction of the net force (and thus acceleration) is to the left.

Answer:

(4) accelerates to the left