Three point shot: getting a friendly bounce

Classical Mechanics Level 1

In basketball, when you're taking a shot, you generally want to aim for the middle of the basket to get a swish (when the ball doesn't touch the rim). But life isn't perfect and this doesn't always happen.

If you want to maximize the chance that your shot goes in, even if you miss the swish and the ball bounces off the rim and/or backboard, what could you do with your shot besides aiming correctly?

Put a forward spin on the basketball Put no spin on the basketball Put a backward spin on the basketball

9 solutions

Arjen Vreugdenhil
Jun 3, 2018

Consider what happens when the ball hits the rim. Without spin, the ball will, on average, bounce forward with the same angle. But with backward spin, static friction between ball and rim will push backward on the ball (since the bottom of the ball is moving forward relative to the center of the ball). This will cause the ball to bounce more vertically, increasing the likelihood that it falls through the basket.

Generally I feel this to be a good intuition. But there are cases when a forward spin would help. How can we prove that those cases are statistically fewer, if we consider the backboard, too?

Laszlo Kocsis - 3 years ago

Forward spin would help if your shot didn't have enough energy to reach the rim, so without spin, instead of bouncing forward the ball would bounce backwards when hittin the rim, and a forward spin would help the ball counteract that backwards bounce. We could suppose there are more forward bounces than backward bounces when hitting the rim, since the shots that make the ball bounce forward have a more similar trajectory to the shots that make a swish. In my opinion, though, the ball spins as a consequence of the tecnique players use to throw the ball instead of the players adopting a throwing technique to make the ball spin.

Roger AB - 3 years ago

Yes, without the backboard, those cases are fewer. I didn't question that.

Laszlo Kocsis - 3 years ago

What effect does the forward spin have on bounces against the backboard, is there a difference if it is in an upward trajectory or if it is in a downward trajectory when hitting the backboard (eg, hitting the rim before the backboard or hitting the baclboard directly)?

I was under the impression that people that went for swish shot were overconfident and the safer more prefereable throw was to bounce it off the backboard. Or is that just for amatures?

Gustaf Carstam - 3 years ago

If the ball hits the backboard with backward spin, the part of the ball that hits the backboard is moving upward due to spin. This will result in a downward force on the ball, making it bounce off more horizontally than without the spin. This might increase the probability of going through the basket or at least hitting the inside of the rim.

Arjen Vreugdenhil - 3 years ago

Other than lay-ups, professional basketball players are aiming for the hoop.

Brian Egedy - 3 years ago

Yes. However, the balls backward rotation will also induce friction with the air before contact with the rim because of opposite movement of the underside of the ball. This will create a downward arcking effect that if shot right, will result in a more vertical entry to the hoop, thus heightening the chance of entry.

jasolikeapro gaming - 3 years ago

someone should post a problem about this.

Roger AB - 3 years ago

I believe a forward spin will give a downward arcking effect like what we see in table tennis. Although, in my opinion, the basketball is too heavy to feel this Magnus effect owing to its very slow spin that the players might give to the ball.

Rohit Gupta - 3 years ago

@Rohit Gupta – Right, the acceleration due to the Magnus effect is negligible.

Arjen Vreugdenhil - 3 years ago

This problem makes the error of ignoring the backboard. If the ball over-travels the target the backboard makes the ball return towards the target. Therefore a forward spin will more likely make target misses bounce off the backboard for a second chance.

A Former Brilliant Member - 3 years ago

Can the Mangnus effect play some role?

Niladri Singha mahapatra - 3 years ago

The Magnus effect can safely be ignored, given that the ball spins relatively slowly and is rather massive.

Arjen Vreugdenhil - 3 years ago

Maryam Bagheri
Jun 4, 2018

just see how the player do this! :)

couldn't say it any better : )

IR J - 3 years ago

But it may be a style point - note that most/all players fail to use the mathematically optimal free throw style https://www.theguardian.com/science/2017/apr/26/granny-style-is-best-way-to-take-a-basketball-free-throw-study-shows

Brian Pingree - 3 years ago

In fact, I play basketball and this how you shoud throw the ball.

Avram Victor - 3 years ago

this technique is taught at a grade school level

John Warden - 3 years ago

Just because it's done does not mean it is the best option, this does not justify the answer.

Simão Faria - 2 years, 11 months ago

Rakshith Venkatesh
Jun 4, 2018

When the ball is thrown, it will have a forward force with it (irrespective of the spin).

The basket is our desired area. So when the ball hits the rim, we'd like it to bounce at the same place to maximize our chances of the ball falling through the basket.

Let's consider different cases when the ball hits the rim: 1. No spin: The ball bounces forward towards the backboard (due to the forward force of the ball itself) 2. Forward spin: This adds to the forward force of the ball and the ball moves towards the backboard with increased speed, thus scuttling our chances 3. Backward spin: This (almost) cancels out the forward force and the ball simply bounces upwards. Since the ball is now directly above the basket, the gravity fall has maximum chances to fall through the basket

What you call "forward force" is called "momentum" in physics. We reserve the word "force" for an external push or pull.

Arjen Vreugdenhil - 3 years ago

You have treated hitting the backboard as failure, but a ball could still go in after it hits the backboard.

On the other hand, if it hits the near rim and bounces backwards then it cannot go in.

Paul Prescod - 3 years ago

Little Narwhal
Jun 8, 2018

Ahem, i play basketball, and that's just what they teach you :)

Alexandre Agriopoulos
Jun 7, 2018

Check the Magnus effect on wiki and you will understand ;)

Happy Ahuja
Jun 3, 2018

Backspin forces the ball to remain near the basket, thus creating more chances for ball to fall in the basket.

at all angles or just hitting the inside of the part of the rim closest to the player? I somehow find this counterintuitive, I would think this only works on the smallest target area of all potential near-shots. and that there would be more opourtunities for the ball to stay near the basket with a forward spin...

But I dont have a fair grasp of bounces and spin so I can have mixed up what the effect is from backwards and forwards spin...

Gustaf Carstam - 3 years ago

Iulian Boruga
Jun 9, 2018

The ball have an inertia force that keep it moving forward. You need to cancel that force with another force, the friction who is transforming the backward spin of the ball in a way that cancel the inertia, and then you get a spectaculous swish!

I have some problems with the translations but i think you are understanding😉😉😉

Benjamin Kunkov
Jun 9, 2018

Yay because I’m cool

Brack Harmon
Jun 6, 2018

Logically, a backward spin is easier to create than a forward spin. I've learned that spinning a ball backwards stabilizes the ball's trajectory allowing it to easily skip on water.

Applying this to Basketball, if a ball with backward spin hits the backboard, it will likely move back towards you and into the net. On the other hand if a ball with forward spin hits the backboard, it will try to move up the backboard loosing it's momentum and will likely miss the net.

Three point shot: getting a friendly bounce

9 solutions

0 pending reports