Question

In this lab you measured the kinetic energy of a car (KE, in Joules) at several velocities (m/s). At the beginning of the lab the car was at rest (v = 0 m/s) and had no kinetic energy. At v = 1.0 m/s, the car had KE = 5.1 J. At v = 2.0 m/s, the car had KE = 19.6 J. At v = 3.0 m/s, the car had KE = 45.1 J. Finally, at v = 4.0 m/s, the car had KE = 79.9 J. The real physics formula is KE = ½mv 2 . Relating this formula to the equation of your best fits line, predict the mass (m, in kg) of the car from this lab.

I've found a linear graph, but I don't know how to predict the mass.

Answer 1

So we plot KE vs v² , this will be a linear graph and the slope of the graph is mass/2.

Hence mass of the car = 2 x (slope of the graph)

Using excel, we got the following linear fit as show below. The linear equation is y = 4.9938 x

The slope of the graph is 4.9938 kg . Hence the mass m = 2(4.9938)kg = 9.9876 kg.