# How can you accurately find the initial velocity of a toy gun?

Disregarding air resistance, how could you find an accurate number for the initial velocity of a toy gun?

## Answers and Replies

jbriggs444
Science Advisor
Homework Helper
Ballistic pendulum? Fire it into a pendulum so that it sticks and see how high the pendulum goes?

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berkeman
Mentor
Disregarding air resistance, how could you find an accurate number for the initial velocity of a toy gun?

Welcome to the PF.

Why would you disregard air resistance? Do you want to know Vo or not?

sophiecentaur
Science Advisor
Gold Member
2020 Award
Welcome to the PF.

Why would you disregard air resistance? Do you want to know Vo or not?

The exit velocity is the velocity, whatever you are firing into. I think, by "disregarding air resistance" he refers to the measurement method. If he is, then observing the maximum height achieved (KE=GPE) would be a way forward (or up haha). The ballistic pendulum would be more accurate and repeatable, once he's got his technique right.

A.T.
Science Advisor
The ballistic pendulum would be more accurate and repeatable, once he's got his technique right.
The pendulum is probably the best way.

But you can also check if your digital camera supports slow motion filming. Some cameras below 500\$ can film at more than 1000fps, which should be enough for a "toy gun". The pixel resolution is usually low, but sufficient if you place the camera right next to the muzzle.