Q.72

Expert-verified
Found in: Page 158

### Physics for Scientists and Engineers: A Strategic Approach with Modern Physics

Book edition 4th
Author(s) Randall D. Knight
Pages 1240 pages
ISBN 9780133942651

# Write a realistic problem for which these are the correct equations.Draw the free-body diagram and the pictorial representation for your problem.Finish the solution of the problem.

Part (a): Suppose we are pulling a block of mass on a rough surface. The coefficient of kinetic friction between the surface is . The force applied on the block is at an angle above the horizontal. What is the frictional force on the block?

Part (b): The free-body diagram is:

Part(c): The values of and are calculated by solving the given equations. The results are , and .

See the step by step solution

## Part (a) Step 1: Given.

Three given equations are:

.

## Part (a) Step 2: Explanation of solution.

The real problem is:

Suppose we are pulling a block of mass on a rough surface. The coefficient of kinetic friction between the surface is . The force applied on the block is at an angle above the horizontal. What is the frictional force on the block?

The three variables in the given equations can be represented by the normal force, acceleration of the block, and frictional force. Hence, the three equations can represent the above problem.

## Part (b): Step 3: Explanation of solution.

The first equation can represent the total force applied to the block. Which is equal to the difference between frictional force and the horizontal component of the applied force.

Since, the block is moving only in direction, the vertical forces are balanced, which is represented by the second equation.

Third equation gives the frictional force .

The free-body diagram is:

## Part (c): Step 5: Calculation.

First solve the second equation to calculate .

Now, substitute the value of in the third equation to calculate the value of .

Now, use the value of in the first equation to calculate the value of .

## Conclusion,

Part (a): Suppose we are pulling a block of mass on a rough surface. The coefficient of kinetic friction between the surface is . The force applied on the block is at an angle above the horizontal. What is the frictional force on the block?

Part (b): The free body diagram is:

Part (c): The values of and are calculated by solving the given equations. The results are, and .