6. Intro to Forces (Dynamics)

A block of mass $m$ is sliding to the right on a rough horizontal surface. The forces acting on the block are its weight $W$, the normal force $N$, a rightward applied force $F$, and a leftward friction force $f$. Which equation correctly represents the block's acceleration $a$?

When a sky diver opens her parachute during free fall, which of the following occurs immediately after the parachute opens?

A $100 \mathrm{kg}$ mass is suspended by two cables attached to a ceiling at points A and B, which are $3 m$ apart. The mass hangs directly below point D, which is $1 m$ from A and $2 m$ from B. Assuming the system is in equilibrium, what is the tension in the cable from A to D?

A rectangular wire loop of length $L$ and width $w$ carries a current $I$ and is placed in a uniform magnetic field $B$ such that the plane of the loop is parallel to the field. What is the magnitude of the total force on the loop?

A force vector $p$ has a magnitude of $p$ and makes an angle $\theta$ with the x-axis. What is the y-component $p_y$ of the force?

If a load is applied straight downward to a stationary object resting on a horizontal surface, which force balances the downward force of the $F\_\mathrm{load}$?

An object is at rest under the influence of two forces, $F_1$ and $F_2$. To keep the object at rest, a third force $F_3$ is added. Which of the following correctly describes the direction and magnitude of $F_3$?

An object moves along a straight line and its velocity-time graph is shown. At position $b$, the velocity is decreasing. What is the direction of the net force acting on the object at position $b$?

A uniform beam of length $L$ and mass $m$ is supported horizontally by a pin at point B, which is located a distance $d$ from one end. If the beam is in static equilibrium and no other supports are present, what is the magnitude of the pin force at B?

Which two principal factors most directly affect the force of air resistance acting on a falling object?

Two point charges, $q=\mathrm{+1}$ C at $x=0$ m and $Q=\mathrm{+4}$ C at $x=10$ m, are fixed on the x-axis. At what point along the x-axis would a proton experience no net force?

When a $F$orce is applied to a rack in the direction shown, which of the following best describes the resulting motion of the rack in a rack and pinion mechanism?

A cantilevered beam is fixed at support A and subjected to external loads. Which of the following sets of support reactions must be present at point $A$ to maintain equilibrium?

Which of the following is a correct expression for the acceleration of the box in scenario 2?

What is the primary force that causes a falling skydiver to slow down after the parachute opens?