6. Intro to Forces (Dynamics)

A particle moves along the x-axis so that its position as a function of time is given by $x=2t^3-9t^2+12t$, where $x$ is in meters and $t$ is in seconds. At what time or times is the particle moving to the right at maximum speed?

Which of the following situations involves an unbalanced force acting on an object?

On September 8, 2004, the Genesis spacecraft crashed in the Utah desert because its parachute did not open. The $210$-kg capsule hit the ground at $311$ km/h and penetrated the soil to a depth of $81.0$ cm. What force did the ground exert on the capsule during the crash? Express the force in newtons and as a multiple of the capsule's weight.

When performing the classic egg drop demonstration, how do $\mathrm{balanced}$ and $\mathrm{unbalanced}$ forces explain why the egg falls into the water after the support is quickly removed?

Two balls of different masses ($m\_1$ and $m\_2$) are dropped from the same height ($h$) in the absence of air resistance. Which ball hits the ground with greater speed ($v$)?

A truss is in static equilibrium with a horizontal member AB subjected to a load. If the member AB is oriented horizontally and supports a vertical load of $1000N$ at its midpoint, what is the force in member AB according to Newton's First and Second Laws?

According to Newton's First and Second Laws, which of the following best explains why a lightbulb in a simple circuit will not light if the circuit is open at one point?

Which of the following examples describes a situation where a car is experiencing a net force ($F\_\mathrm{net}$)?

Which of the following best describes Galileo's contribution to the study of motion?

When you drive on icy roads, which of the following physical quantities is most directly affected, according to Newton's First and Second Laws?

Which of the following best describes Newton's First Law of Motion?

According to Newton's Second Law, if an unbalanced force acts on an object, what will happen to the object's motion?

According to the second part of Newton's First Law, what happens to an object at rest if no net external force acts on it?