The problem involves calculating the average force of friction acting on a 5kg box that slides to a stop after being tossed across the floor at an initial speed of 4 m/s over a duration of 3 seconds.
The discussion is active with participants sharing various approaches to the problem. Some guidance has been provided regarding the use of impulse and the relationship between force, mass, and acceleration. Multiple interpretations of the calculations are being explored.
Participants are working within the constraints of a homework assignment, and there is a focus on understanding the underlying principles rather than arriving at a definitive solution.
That would be impulse, f*tStephen Tashi said:You can calculate the initial momentum of the box. The momentum of the box is zero when it stops moving. What formula relates force to a change in momentum?
keithcuda said:That would be impulse, f*t
and f=m*a
so the impulse would be, (m*a)*t
impulse=(5*(4/3))*3=20
keithcuda said:That would be impulse, f*t
and f=m*a
so the impulse would be, (m*a)*t
impulse=(5*(4/3))*3=20
OK, so then I know that t=3, and I(impulse)=20, If F is unknown then F=I/T= 6.66NStephen Tashi said:Yes, if you use 4/3 as average acceleration. However, to solve for average F in equation for impulse, you'd do better to keep F as an unknown instead of writting it as m*a. To solve for F using F = m*a , you could claim that average force = mass * average acceleration.
keithcuda said:OK, so then I know that t=3, and I(impulse)=20, If F is unknown then F=I/T= 6.66N