Question

What units will we use for the forces in this lab? What is the meaning of the Equilibrant? How do the Equilibrant and Resultant vectors relate to each other? What are the three approaches we will use to analyze the vector addition of forces in this lab? Describe them briefly.

Answer 1

(1) ans

the units used in the forces for lab is newtons

(2) ans

Equilibrant force :-Equilibrant force is a force which brings equilibrium state. It is considered to be the equal and opposite of the resultant force. Equilibrant force is the force, which keeps any object motionless and acts on virtually every object in the world that is not moving.

(3) ans

They relate to each other because they are both vectors. Equlibrant is when forces are equal, but opposite each other, thus brings an object to an equilibriam state. A resultant vector is two or more vectors acting on an object in opposite directions which will cancel the forces making it zero.

Well, that is what it says in my prelab assignment. It says, "A force equal to but opposite in direction to the resultant is called the equilibrant, E, and is that force which, together with the resultant force, will produce equilibrium, i.e. E+R=0.

(4) ans

Equilibrium with Three Forces

We shall first study the equilibrium of the small ring when there are three forces acting on it. Two of the forces

(F₁ and F₂)

will be fixed and the third one

F₃

adjusted until equilibrium is reached.

• 1

  If necessary, level the force table using the small bubble level placed on the table's surface.

• 2

  Choose any two masses you like in the range 100-300 g, and place each mass on a weight holder. Use the electronic balance to measure each of the masses including the holder. Designate the measured masses as

  m₁ and m₂.

  The uncertainty of these measurements should be limited to the precision of the balance.

• 3

  Place the pin in the middle of the force table and place the ring over the pin. Attach two of the four pulleys provided to the force table at any position other than zero degrees. Record the value of θ₁ and θ₂. The uncertainty in these angles should be limited to the precision to which you can read the angles on the force table.

• 4

  Run two of the strings (attached to the ring) over the pulleys, and suspend the masses that you have chosen at the appropriate angles

  (m₁ at θ₁ and m₂ at θ₂).

  The tension in the two strings acts on the ring with forces

  F₁ and F₂,

  each with a magnitude equal to the weight of the corresponding mass and holder

  (m₁g and m₂g)

  suspended at the end of each of the strings.

• 5

• Pull one of the remaining strings in various directions until you locate a direction in which the ring is freed from the pin when you apply the right amount of force. Attach a third pulley at this position. Run the string over the pulley and attach a weight holder to the string. Add weights to the weight holder until the ring pulls away from the pin, so that the pin is not necessary to hold the ring in place. This last added force is the (equilibriant) force

  F₃ (m₃g).

  It may be necessary to make minor adjustments to the angle to obtain a precise measurement. Make sure that the strings are stretched radially and the pin is at the center of the ring. Estimate the uncertainty in the equilibrant force by adjusting the mass and angle until the system is no longer in equilibrium.