Question
Three forces act on a block at rest on an incline: agravitational force, a normal force by the incline and africtional by the incline. Which of the following statementsis true (only one is true)? 1 - By Newton's 3rd law, the normal force must equal theweight. 2 - Friction is the largest force since it is overcominggravity to keep the block from sliding. 3 - The normal force is greater than the weight. 4 - The normal force is equal to the weight, but they are nota 3rd law pair since they point in different directions. 5 - The normal force is smaller than the weight. Explain your reasoning: Three forces act on a block at rest on an incline: agravitational force, a normal force by the incline and africtional by the incline. Which of the following statementsis true (only one is true)? 1 - By Newton's 3rd law, the normal force must equal theweight. 2 - Friction is the largest force since it is overcominggravity to keep the block from sliding. 3 - The normal force is greater than the weight. 4 - The normal force is equal to the weight, but they are nota 3rd law pair since they point in different directions. 5 - The normal force is smaller than the weight. Explain your reasoning:
Explanation / Answer
1) not true, normal force = (mg)(COS ) < weight(mass*gravity) 2) not necessariy true, small produces small frictionforce 3) not true, normal force = mg COS < mg 4) normal force does not equal mg 5) true, mg COS is always < mg