Can you solve it? (Sensor based physics problem)

[hgpt]

Here's the problem:

You have a ceiling fixed punch bag. Find the minimum sensor setup to determine:
1. The force of a punch in the bag

2. The acceleration of the punch

3. The speed of the punches (if multiple punches are thrown)

Limitations:
1. Sensors must only be attached to the bag. NO sensor can be attached to the person.

2. The bag is punched in a limited vertical area.

Justify answer with sensors and calculations.

Can you solve it?

Edited July 5, 2017 by hgpt

[fiveworlds]

You could use 1 variable resistor which rotates when the bag is punched then a microcontroller to count the punches etc.

[Bender]

A webcam and tracker software. Tracker works great because it can automatically extract acceleration info.

 

Then relate the acceleration to the force with F=ma and m the mass of the bag.

 

It would be nice to attach some clear markers on the bag.

 

This probably belongs in engineering.

[hgpt]

I'm not able to use a webcam and a tracker software. Only sensors!

There's one other thing: the bag is fixed to the floor with a spring.
Some known values are:

- mass of the punch

- mass of the bag

- the distance R at which the puncher is hitting relative to the tip of the bag

- acceleration on all 3 axis (by using an accelerometer)