Chapter 3, Problem 4STP

To determine

The time interval for which the net force on the object is smallest.

Answer to Problem 4STP

Option (D) is correct.

Explanation of Solution

Introduction:

The net force on the object depends on the mass and acceleration of the object. The slope of the velocity-time describes the acceleration of the object.

The slope of the speed time graph is same as the acceleration of the object. If the slope is large in the graph, then the acceleration becomes high. The longer the slope of the graph then greater is the force on the object and smaller is the slope of the graph then lower is the force on the object.

The slope of the object for time interval $0\text{s}$ to $1\text{s}$ is $8\text{m}/{\text{s}}^2$ .

The slope of the object for time interval $1\text{s}$ to $2\text{s}$ is $7\text{m}/{\text{s}}^2$ .

The slope of the object for time interval $2\text{s}$ to $3\text{s}$ is $3\text{m}/{\text{s}}^2$ .

The slope of the object for time interval $4\text{s}$ to $5\text{s}$ is $1\text{m}/{\text{s}}^2$ .

The slope for the time interval $4\text{s}$ to $5\text{s}$ is least. So, the net force on the object is smallest for time interval $4\text{s}$ to $5\text{s}$ .

Conclusion:

Thus, the net force on the object is smallest for time interval $4\text{s}$ to $5\text{s}$ .