Math Worksheets

Question: Physics pendulum problem help?

alright, so I’m supposed to be doing this preliminary worksheet for a class so my TA can see where I am in the math department. This is all fine and dandy, except I haven’t been in a math class for months, and have forgotten a lot of stuff I need to know. So, firstly, it would be helpful to know the conversion formula for miles per hour to kilometers per hour. Secondly, I’m a little confused about the pendulum formula
time(in seconds)=2(pi)√length(in meters)/9.8 m/s squared. I know solving for any variable involves balancing each side of the equation, but when I tried that, I came p with some crazy answers. So, maybe you can tell me what I’m doing wrong. Thanks!Your help is greatly appreciated!

Answer: first part:

there are 5280 ft/mile
and 3.28 ft/meter

so: there are 5280ft/mi/{3.28ft/meter} = 1609.75 meter/mile
or 1.61 km /mi

so there are 1.61km/hr for every 1 mi/hr, so if the speed limit is 50 miles/hr, it is the same as 80.5 km/hr

second part:

P=2πsqrt[L/g] (g is the symbol for 9.8m/s/s

to solve for L

square both sides:

P^2=4π^2(L/g)
L=gP^2/4π^2

hope this helps

An Arc Length Word Problem