How Do You Calculate Normal Force and Work Done in Physics Problems?

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To calculate the normal force for a 52 kg box, the force of gravity is determined as 509.6 N, which is equal to the normal force acting upward. The normal force is considered positive, while the gravitational force is typically treated as negative in physics problems. The coefficient of kinetic friction is 0.25, which affects the frictional force acting on the box. It's important to differentiate between Newtons, a unit of force, and Joules, a unit of work or energy, as they measure different concepts. Understanding these principles is crucial for solving related physics problems effectively.
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52 kg box is pushed 7.0 meters by a force with a magnitude of 149 N. The coefficient of kinetic friction is 0.25. Determine normal force, force of gravity and frictional force.

For the normal force I have 52 * 9.8 = 509.6 N Which is also the the force of gravity. However which is positive and which is negative? I assume normal force is positive since it pushes up against gravity pushing downward? Also, how would I convert Newtons into Joules?
 
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LostInScience said:
52 kg box is pushed 7.0 meters by a force with a magnitude of 149 N. The coefficient of kinetic friction is 0.25. Determine normal force, force of gravity and frictional force.

For the normal force I have 52 * 9.8 = 509.6 N Which is also the the force of gravity. However which is positive and which is negative? I assume normal force is positive since it pushes up against gravity pushing downward? Also, how would I convert Newtons into Joules?
As long as you are consistent, it doesn't matter which direction is positive or negative. Generally, down is usually taken as negative. Now don't confuse Newtons, a unit of force, with Joules, a unit of energy or work. How much work does each force do on the box?
 

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