Log In Start studying!

Select your language

Suggested languages for you:
Answers without the blur. Sign up and see all textbooks for free! Illustration


Fundamentals Of Physics
Found in: Page 117

Answers without the blur.

Just sign up for free and you're in.


Short Answer

Some insects can walk below a thin rod (such as a twig) by hanging from it. Suppose that such an insect has mass m and hangs from a horizontal rod as shown in Figure, with angle θ=40° its six legs are all under the same tension, and the leg sections nearest the body are horizontal. (a) What is the ratio of the tension in each tibia (forepart of a leg) to the insect’s weight? (b) If the insect straightens out its legs somewhat, does the tension in each tibia increase, decrease, or stay the same?

(a) Ratio of the tension in each tibia to the insect’s weight is 0.26 .

(b) Tension will decrease in each tibia when the insect straightens out its legs.

See the step by step solution

Step by Step Solution

Step 1: The given data

The angle of the leg joint, θ=40°

Step 2: Understanding the concept of the free-body diagram

From the free-body diagram of the insect, we can calculate the tension in both cases. According to the conservation law, all forces acting on the body are to be balanced for the body to be at equilibrium. So, the total force in a given direction is zero.


Since, the total forces acting on the body are balanced in the given direction,

F=0 (i)

Step 3: a) Calculation of ratio of tension to insect’s weight

We take the summation of all forces in y direction to be zero, so from equation (i), we get

FY=0 Tsinθ-mg=0 ( from free body diagram) Tsinθ=mg

As there are 6 legs of the insect, we get the force from 6 sine components. Hence, we get,

6×T×sin40°=mg Tmg=16×sin40° =0.259 0.26

Hence, the value of the required ratio is 0.26.

Step 4: (b) Finding the behavior of tension

As the insect straightens out its legs, the value of angleθwould increase. Since the sinθ is inversely proportional to the tension, as value ofθincreases, the tension would decrease.

Most popular questions for Physics Textbooks


Want to see more solutions like these?

Sign up for free to discover our expert answers
Get Started - It’s free

Recommended explanations on Physics Textbooks

94% of StudySmarter users get better grades.

Sign up for free
94% of StudySmarter users get better grades.