A 5.5 kg bowling ball initially at rest is dropped from the top of a 12 m building. It hits the ground 1.75 s later. Find the net external force on the falling ball.

Question

yrelhan4 · Answer

s=1/2at^2
you have s and t find a.
net force=ma. plug and solve.

anonymous · Answer

What is s?

yrelhan4 · Answer

s-->distance travelled
a--> acceleration due to gravity here
t-->time taken

anonymous · Answer

Okay, thanks:)

yrelhan4 · Answer

cheers!

anonymous · Answer

I 431.2N but that isn't an option..

yrelhan4 · Answer

43.12 N is the answer.

anonymous · Answer

So this is what I did..
s=12m
a=?
t=1.75s

12=((1.75)^2a)/2
12=(3.0625a)/2
24=3.0625a
a=7.84

netforce=55*7.84
netforce=431.2N

yrelhan4 · Answer

Net acceleration. a = 2*12/1.75² 
Net force ma = 5.5* 2*12/1.75² = 43.12 N

anonymous · Answer

I get what your saying now. But the only problem is my choices are 120N, 54N, & 0N. But I can rule out 0N automatically

yrelhan4 · Answer

hmm. no idea. sorry.

anonymous · Answer

Its okay, thanks for your help though :) I really do appreciate it

yrelhan4 · Answer

you're welcome. good luck. :)