Question

a box is at rest on a floor. then a student drags the box across the floor. the diagram shows the horizontal forces acting on the box as it is being dragged.

diagram: 18n left, 3kg box, 30n right

based on newton’s second law, what is the velocity of the box 4 s after the student starts dragging it?

a) 4 m/s
b) 32 m/s
c) 16 m/s
d) 8 m/s

Explanation:

Step1: Calculate net force

Net force \( F_{net} = F_{right} - F_{left} = 30N - 18N = 12N \)

Step2: Find acceleration using \( F = ma \)

Rearrange formula: \( a = \frac{F_{net}}{m} \), where \( m = 3kg \). So \( a = \frac{12N}{3kg} = 4m/s^2 \)

Step3: Calculate velocity using \( v = u + at \)

Initial velocity \( u = 0m/s \) (starts from rest), \( t = 4s \), \( a = 4m/s^2 \). So \( v = 0 + 4m/s^2 \times 4s = 16m/s \)

Answer:

C. 16 m/s