This should be simple...?

Question

I'm taking a basic physics class after several years of not taking any kind of math or physics classes.  This question should be incredibly simple, but I'm absolutely stuck for reasons I can't understand.  I never had any problems with advanced math, but I'm stumped now.

how long would it take an object to fall 2 m?  We can use 10m/s2.

I see time, acceleration, and distance being the variables, but for the life of me I can't put them together, and my book doesn't give me any help. 

How do you work this out?

Anthony · Accepted Answer

Use s = ut + 1/2 at^2
where u = initial velocity = 0, a = acceleration = 10m/s^2, t = time in seconds s = distance in metres = 2m.
2 = 0 + 5t^2
2/5 = t^2
0.4 = t^2
0.632s = t

dawgdays · Answer

It's algebra. You can start with the equation

D = D(initial) + V(initial)*t + 0.5*a*t^2

Since V(initial) is zero and D(initial) is zero at the drop point, and the a is -10 m/s^2 (down is negative by convention), you end up with

-2 = -10*t^2
2/10 = 1/5 = t^2
t = sqrt(1/5)

Make sense?

Trending News

This should be simple...?

2 Answers