# Trajectory of arrow vs golf ball

**URL:** <https://boards.straightdope.com/t/trajectory-of-arrow-vs-golf-ball/808005>\
**Category:** In My Humble Opinion\
**Created:** [February 2, 2018, 6:20am UTC](https://boards.straightdope.com/t/trajectory-of-arrow-vs-golf-ball/808005 "2018-02-02T06:20:04Z")\
**Posts on this page:** 2\
**Page:** 2

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**Author:** ![newme](https://avatars.discourse-cdn.com/v4/letter/n/e0b2c6/32.png) [@newme](https://boards.straightdope.com/u/newme)\
**Post date:** [February 5, 2018, 9:27pm UTC](https://boards.straightdope.com/t/trajectory-of-arrow-vs-golf-ball/808005/21 "2018-02-05T21:27:18Z")

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> [@HoneyBadgerDC](#):
>
> I am going to change my question to just one factor maybe it will be clearer. Does the impact force on the ball increase as the angle of the club face decreases. In other words ignore distance and trajectory. Would a ball hit with a 0 degree face have more energy in it than a ball hit with a 20 degree face.

Simple answer is yes. I treated it as an example of a “spherical cow” physics problem. Assuming my math is correct, these are the results.

Golf driver head moving at 100 mph with exactly four times the mass of a golf ball strikes the ball squarely, 0 degree face. Assume no golf club shaft, no golfer, momentum and translational kinetic energy conserved, so no spin on the ball or club head.

The ball will rebound at exactly 160 mph, and exactly 64% of the kinetic energy in the club head is transferred to the ball.

Next, same club head moving at the same speed, but now the ball rebounds at 45 degrees.

The ball’s speed is now only √2\*80 = ~113 mph, and only 32% of the kinetic energy is transferred to the ball, exactly half of the first trial.

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**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\
**Post date:** [February 6, 2018, 2:32am UTC](https://boards.straightdope.com/t/trajectory-of-arrow-vs-golf-ball/808005/22 "2018-02-06T02:32:33Z")

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> [@newme](#):
>
> Simple answer is yes. I treated it as an example of a “spherical cow” physics problem. Assuming my math is correct, these are the results.
> 
> Golf driver head moving at 100 mph with exactly four times the mass of a golf ball strikes the ball squarely, 0 degree face. Assume no golf club shaft, no golfer, momentum and translational kinetic energy conserved, so no spin on the ball or club head.
> 
> The ball will rebound at exactly 160 mph, and exactly 64% of the kinetic energy in the club head is transferred to the ball.
> 
> Next, same club head moving at the same speed, but now the ball rebounds at 45 degrees.
> 
> The ball’s speed is now only √2\*80 = ~113 mph, and only 32% of the kinetic energy is transferred to the ball, exactly half of the first trial.

Perfect, that’s exactly what I was looking for.

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