Engineering, 30.03.2020 21:05 shygrl05

Lumber jacks use cranes and giant tongs to hoist their goods into trucks for transport. Fortunately, smaller versions of these devises are available for weekend warriors who want to play with their chain saws. Let us model the illustrated tongs as a planar mechanism that carries a log of weight N. Given the following dimensions: 35 mm 10 mm 40 mm 230 mm 85 mm 45 mm 10 mm 35 mm 345 mm determine the force in N and moment in Nm that our worker exerts on the tongs. Also determine the pinching force magnitude in N that the tongs exert on the log; i. e. determine the horizontal force that the tong's teeth exert on the log. Assume the point is centered between the tong's teeth. Matlab input: a

Answers: 2

Show answers

Answers

Answer from: sophoyak

Complete Question

Lumber jacks use cranes and giant tongs to hoist their goods into trucks for transport. Fortunately, smaller versions of these devises are available for weekend warriors who want to play with their chain saws. Let us model the illustrated tongs as a planar mechanism that carries a log of weight 210 N. Given the following dimensions: 35 mm 10 mm 40 mm 230 mm 85 mm 45 mm 10 mm 35 mm 345 mm determine the force in N and moment in Nm that our worker exerts on the tongs. Also determine the pinching force magnitude in N that the tongs exert on the log; i.e. determine the horizontal force that the tong's teeth exert on the log. Assume the point E is centered between the tong's teeth.

The diagram for this question is shown on the first uploaded image

The force P is P= 210 N

and the moment M is $M = -48.3N \cdot m$

The horizontal force that the tong teeth exerts is F_T =89.67N

Explanation:

First let denote the dimension to corresponding to the diagram

$a=35mm , b= 10mm, c= 40mm, d= 230mm, e= 85mm,f= 45mm,\\g= 10mm,h=35mm,i=345mm.$

Next looking at the diagram let us consider the vertical direction

At equilibrium

$\sum F_{vertical} =0$

This mean that

P+ W = 0

Since they are acting in opposite direction the equation becomes

P - W = 0

=> P= W

=> P= 210 N

At Equilibrium Moment about F gives

$\sum M_f = 0$

=> F_T * (e +f + g+ h+ i) - F_T * (e+ f+g+ h+i) - W *d -M =0

=> M = -W *d

=> M = -210 * 0.230

=> $M = -48.3N \cdot m$

Here F_T is the horizontal force that the tong teeth exerts

Now let consider the part BAF of the system as shown on the second uploaded image

Now the angle $\theta$ is mathematically given as

$tan \theta = \frac{g+h}{a}$

=> $\theta = arctan \frac{g+h}{a}$

$= arctan (\frac{10+35}{35} )$

=52.125^o

Now at equilibrium the moment about A is

$\sum M_A = 0$

=> $P * (c+d) +M + F_{BC} cos \theta *f+F_{BC}sin\theta *(a+b) =0$

$210 * (0.040 + 0.230)-48.3+F_{BC} cos (52.125^o)*0.045+ F_{BC}sin(52.125^o)$ * (0.035 +0.010) =0

=> $10.29 +F_{BC} (0.02763+0.03552) =0$

=> $F_{BC} =\frac{10.29}{0.06315}$

=> $F_{BC} = - 162.925 N$

Looking at the forces acting on the teeth as shown on the third uploaded image

At Equilibrium the moment about D is

$\sum M_D = 0$

=> $\frac{W}{2} *d - F_T *(i+h) -F_{BC} cos \theta *h -F_{BC} sin \theta * (b+c) =0$

=> $\frac{210}{2} * 0.230 -F_T (0.345 +0.035) - (-162.925)cos(52.125^o) *0.035\\-(-162.925)sin(52.125^o)(0.010 +0.040) =0$

=> 34.081 = F_T(0.345 +0.035)

=> F_T =89.67N

Lumber jacks use cranes and giant tongs to hoist their goods into trucks for transport. Fortunately,

Answer from: Quest

answer:

try looking it up that is always

explanation:

Answer from: Quest

Answer:

the answer is d.

explanation:

Other questions on the subject: Engineering

Engineering, 04.07.2019 18:10, alyssabailey7545

Give heat transfer applications for the following, (i) gas turbines (propulsion) ) gas turbines (power generation). (iii) steam turbines. (iv) combined heat and power (chp). (v) automotive engines

Answers: 1

continue

Engineering, 04.07.2019 18:20, rjone8429

Asimple rankine cycle uses water as the working fluid. the water enters the turbine at 10 mpa and 480c while the condenser operates at 6 kpa. if the turbine has an isentropic efficiency of 80 percent while the pump has an isentropic efficiency of 70 percent determine the thermal efficiency

Answers: 1

continue

Engineering, 04.07.2019 18:20, jessie8022

Apiston-cylinder device contains 0.1 m3 of liquid water and 0.9 m3 of water vapor in equilibrium at 800 kpa. heat is transferred at constant pressure until the temperature of water reaches 350 °c. determine (a) the quality of water at the initial state (b) the work associated with this process, (c) the heat associated with this process.

Answers: 2

continue

Engineering, 04.07.2019 19:10, kimmy6973

What is creep? what is stress relaxation?

Answers: 1

continue

You know the right answer?

Lumber jacks use cranes and giant tongs to hoist their goods into trucks for transport. Fortunately,...