Gravity would have the least effect on the movement of which of t...

Question

Gravity would have the least effect on the movement of which of the following? (Explain your answer.)
a. a salmon
a. a snake
a. a sparrow
a. a grasshopper

Accepted Answer

Welcome back Everyone. Here's our next question. It says which of the following forces must be overcome for locomotion to occur. And as we look at our answer choices, we see, we have three different types of forces offered as possibilities. Along with choice D. Is both A. And B. And choice. He is both B and C. So we see that we can have more than one force here. So let's think about of course locomotion is that active travel from place to place one place to another. So let's think about what forces need to be overcome. Force an animal to move itself actively from one place to another. Well first you have the resistance of whatever medium you're moving through or over and that is um friction. The force of friction has to be overcome. And we see choice B. Here is frictional force but when we think about it, there's yet another force that needs to be overcome. That force that's pulling everything towards the earth. And in order for instance to walk you not only have to have your leg muscles moving you forward in space, they also have to keep you from falling down. So that is gravity. So friction and gravity both need to be overcome and have energy expended to overcome them. So Choice A. Is gravitational force. Uh We have one more force on your choices magnetic force but that's not something we have to overcome to move through space. So C. Is not our answer nora ze, which is both B. And C. Um but our answer is choice D. Which is both A. And B. Both gravitational force and frictional force need to be overcome for locomotion. And one thing we should also note is the amount of energy that needs to be expanded and the significance of needing to overcome that force depends on the environment that are particular animals. In. So for instance for aquatic animals, the force of friction needs the most energy to be overcome. Water is dense and offers lots of resistance to movement through it. So the most energy needs to be used to overcome friction as opposed to gravity because of that density of water it supports most of the animals weight. So the animal doesn't need to expend a lot of energy to overcome gravitational force. But land animals, however, friction needs the least energy to overcome at least at moderate speeds. Air offers little resistance to movement through it. Um Of course very high speeds. Air resistance will be more significant and the only significant friction needs to be overcome is at that point of contact between the body and the ground. So if you're walking your foot, the friction of your foot interacting with the ground as you move is the only friction that needs to be overcome significantly, but gravity needs the most energy to overcome because air doesn't support the body weight in any significant way. So for instance, your leg muscles have to do work both to move you through space and to keep you from falling down. So again depending on the location, the environment, aquatic or land depends on which force. More energy must be expended to overcome for locomotion to occur. So our answer choice again, which of the following forces overcome? Choice D. Both A and B. C. You in the next video.

Gravity would have the least effect on the movement of which of the following? (Explain your answer.) a. a salmon a. a snake a. a sparrow a. a grasshopper

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