6. Intro to Forces (Dynamics)

A person is running on a track. Which of the following forces propels the runner forward?

Why does bending your legs when running enable you to swing your legs to and fro more rapidly?

According to Newton's First Law, what will a baseball that is standing still on a table do if no net force $F\_\mathrm{net}$ acts on it?

According to Newton's Second Law, which force is responsible for causing the acceleration of an object ($F=ma$)?

Which of the following is the best example of an unbalanced force acting on an object?

Which of the following equations correctly expresses Newton's Second Law, relating force, mass, and acceleration?

A horizontal shaft is supported by a smooth thrust bearing at point A and a smooth journal bearing at point B. If a force $F$ is applied perpendicular to the shaft at its midpoint, which statement best describes the reaction forces at the supports according to Newton's First and Second Laws?

When switch S in the figure is closed at time $t=0$, which of the following best describes the motion of a block of mass $m$ attached to a horizontal frictionless surface and pulled by a constant force $F$?

Which of the following explanations is contrary to Newton's first law of motion?

According to Newton's First Law, when an object is acted upon by balanced forces ($F=0$), which two types of motion can it experience?

According to Newton's Second Law, what does the sum of forces acting on an object equal to? $\sum F=ma$

According to Newton's First Law, what will happen to the rock after you kick it and it slides along the concrete sidewalk, assuming no other forces act on it?

If a problem involving Newton's Second Law ($F=ma$) was solved assuming negligible air resistance, would the answer change if there were appreciable air resistance present?

According to Newton's First and Second Laws, what is the primary cause of an object's change in motion?

Which of the following best describes balanced forces according to Newton's First Law?