Here is where I am at:
Still am attempting an energy approach so E_pot=E_k+E_rot
I still have the same acceleration I calculated from the falling mass being dropped to the floor where
t=10.42s
y_i=.64m
so: a_y=(2y_i)/t^2 gives a_y=-.0118m/s^2
and the the final velocity of the...
Ok I replaced the R in (v/R) with r and plugging it in got 12.002 kg which is a very reasonable answer. I understand the need to account for small radius of the axle; however, I'm not sure I see the clear connection. Why would it not matter which R I replace with r?
The string was wrapped around the axle and we do know the radius of the axle. Also, it didn't wrap over itself too much changing the radius felt by the string. Lastly, yes the string was longer than required to reach the floor.
You are absolutely correct. My mistake, I used y_f=y_i+v_i *t+.5a_yt^2 where y_f is 0 and v_i is 0. Then I used that acceleration to find final velocity. I've been thinking, will the string being attached to the an axle change the approach. I think that may be where my mistake is. I sort of...
Thanks very much for responding. I found the velocity using kinematics. We recorded the time it took the block to fall to the ground and then with the known height and an initial velocity of 0 I found the acceleration using v_f=v_i+a(Δt). After that I found the final velocity with...
Homework Statement
The problem is I need to estimate the mass of a (solid equally distributed mass) disc which has an axle on which a string is tied and then attached to a (hanging) 1.022 kg mass. We wound the wheel up moving the hanging mass to a height of 0.64 m off the ground. At this point...
The question I am having difficulty with states that it requires 123 J of work to stretch a very light ideal spring from a length of 1.4m to a length of 2.9m. What is the value of the spring constant?
My thinking was that the work required would be equal to the spring force so I set up...