6. Intro to Forces (Dynamics)

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?

A force of magnitude $10$ N acts at an angle of $30°$ above the positive x-axis. What are the x and y components of this force?

A uniform rectangular gate of width $w$ and height $h$ is submerged vertically in water with its top edge at the water surface. What is the magnitude and direction of the force that must be applied horizontally at the bottom of the gate to keep it in equilibrium against the hydrostatic force of the water?

A boat is anchored in a river where the current exerts a force of $500N$ downstream. If the anchor rope makes an angle of $30°$ with the riverbed and holds the boat stationary, what is the magnitude and direction of the anchoring force exerted by the rope?

Which of the following best describes the shape of the shear force diagram for a simply supported beam of length $L$ subjected to a single concentrated load $P$ at its midpoint, following the standard sign convention (positive shear causes clockwise rotation of the segment on which it acts)?

Which of the following best describes the shape of the bending moment diagram for a simply supported beam subjected to a uniformly distributed load along its entire length?

A $20 \mathrm{kg}$ box is suspended at rest by a vertical strap. To what tension must the strap be adjusted to provide the necessary upward force to keep the box stationary? (Assume $g=9.8 m/s^2$.)