The Greatest Class On Earth

(I’m Sucking Up a Lot Here)

A Sample Problem

This problem comes from the Halliday Resnick Walker Fundamentals of Physics: Fifth Edition. It is problem 33E on page 31.

The head of a rattlesnake can accelerate 50 m/s/s in striking a victim. If a car could do as well, how long would it take to reach a speed of 100 km/h from rest.?

We know that (a) is 50 m/s/s, (v) is 100 km/h, and that (Vo) is 0. We want to find (t). If we do a unit analysis to convert 100 km/h to 27.78 m/s use the equation,

we can solve for t, and then plug in the numbers to find how long it takes.

t = (v-Vo)/ a

t = (27.78 m/s )/ 50 m/s/s

t = .56 seconds