Question

Why is it okay to neglect friction in this experiment? Justify your answer with your calculations of percent differences.

This experiment involved a cart gliding on an air track (constant mass, and acceleration - measured time it took cart to move at different distances AND different masses and the resulting acceleration - measured time it took cart to move at a uniform distance). Percent differences were calculated for acceleration and mass.

Answer 1

When cart is gliding on air track the forces on the cart might be Buyoncy upward and gravity downward, which is balanced,

The other force might be the force applied to give the initial velocity, and the horizontal fluid friction which depends on viscosity.

As viscosity of air effectively is very less, friction can be neglected.

THis can be identified calculating the velocity and identifying percentage changes over different times.

Let us assume time taken to travel a distance x = t seconds. Also measure the time it took to travelnext x metres. If the time taken is very close to t , i.e a bit greater but with in a percentage error of tolerance say 1% you can say that body is moving uniformly.

This can be done for different masses.