Question

M4. Discussion: Frictionless World

Topic

In this module, we examined the concept of friction and how it affects everything we do. Air resistance is an important type of friction that you don’t want to forget about as you prepare your post. Consider what the world would be like without friction. For example, in a world without friction, the pitcher in a baseball game can still pitch the ball because he can push off the pitching rubber. The pitching rubber is the rubber slab atop the pitching mound that a pitcher uses to push off to gain velocity. But what happens when the batter swings or when the ball hits the catcher’s mitt?

Now, think of one of your favorite sports or another activity you enjoy. How would the action of that activity be different in a world without friction? In your initial post to the discussion, describe your activity and then respond to the following:

1. Describe at least three ways your activity would change if friction were taken out of the scenario.
2. Does friction make it easier or harder to participate in your activity?
3. What are some advantages and disadvantages that you might encounter if there wasn’t friction in our world?

Finally, be sure to respond to at least two of your peers’ discussion posts.

Answer 1

in a frictionless world, when the batter hits the ball the ball would fly off and wont stop because when it is in air the air is frictionless so it would attain an unusually large arc before it hits the ground because of gravity after that it will go through infinite amount of bouncing because niter the air nor the ground exert any friction on the ball. For elastic coefficient the bounce height will decrease slowly but it wont stop the ball from rolling away - unless something explicitly confines it like the stadium wall - even in that case it will bounce around the whole stadium.

If the catcher tries to hold it with their mitt, the ball will slip off immidiately; this happens because in most cases there is an angular opening where the ball is confined in the mitt, that means there is an outward force works on the ball but in usual cases the friction nullifies it. Without the friction to resist, the force slips the ball out of the mitt and it starts to roll off, because the ground has no friction as well.

The considered activity here is running. It fully depends on the the frictional force :

• Standing with the leg slightly bent out becomes impossible because it will slip off
• taking a stride becomes impossible because friction from ground supplies the force for motion
• Once in motion, stopping is impossible; in the case of falling down, there is no way of getting up.

Friction definitely makes it harder to run.

In a frictionless world:

• Cars wont need any significant fuel to run; but they will be impossible to stop.
• Meteor and asteroids will hit the Earth all the time because there is no air friction to burn them off
• Fans wont take any energy to continue running, once on they will rotate forever.
• Pendulum clocks will run forever; no air is stopping them from swinging.
• Every screw and nut will slip off of their threading
• There will be no clothing, threads are held and weaved together on the basis of interlaced friction.