Physics

Physics

Problem

A box of mass 20 kg20\,\text{kg} is pushed horizontally with a force of 70 N70\,\text{N} to the right. A frictional force of 10 N10\,\text{N} acts to the left. Calculate the magnitude of the box's acceleration. a) 4 m s−24\,\text{m\,s}^{-2} b) 3 m s−23\,\text{m\,s}^{-2} c) 2 m s−22\,\text{m\,s}^{-2} d) 3.5 m s−23.5\,\text{m\,s}^{-2}
Intuitive explanation

The key is recognizing that net force determines acceleration, not the applied force alone. Find the total force by combining the push to the right with friction opposing it, then use Newton's second law (Fnet=maF_{\text{net}} = ma) to find how quickly the box speeds up. The direction of the net force tells you the direction of acceleration.

Intuitive explanation

The key is recognizing that net force determines acceleration, not the applied force alone. Find the total force by combining the push to the right with friction opposing it, then use Newton's second law (Fnet=maF_{\text{net}} = ma) to find how quickly the box speeds up. The direction of the net force tells you the direction of acceleration.

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