# How can you ensure you pull a mass at a constant velocity

• Nick tringali

#### Nick tringali

In an experiment I hope to carry out, one of my "constants" are velocity (constant velocity). I must say a way I will keep this value constant. For example I can not say "I will try my best to pull mass at a constant velocity" "I will take a video of the experiment. When I examine the video, I will measure the time for the reference point on the block to pass the markings. This data will be included in the report. I will consider the velocity to be constant if the time to travel through equally spaced markings is within + or – 5% of each other"

Don't pull it by hand. Use a motor with appropriate gearing.

Nick tringali
Thanks A.T. The problem is I do not have a motor this must be done by hand

Without the details of the experiment and what equipment you have available, nobody can help you.

You should practise moving whatever it is at a constant speed ... pick the speed, say 10cm per second, mark out 10cm intervals and move the object past each 10cm mark when your watch ticks off each second. Something like that. The alternative is improvising some sort of machine.
If you have an old turntable, you can attach a bobbin to the middle and use it to wind a thread attached to the object.

Thing is - neither of these suggestions work if you are supposed to push a car.
Details are important.

Nick tringali
Thanks Simon, both of your suggestions will work.

Simon Bridge
"I must say a way I will keep this value constant."
Very low friction? Are wheels allowed?