Finding distance using force, acceleration, timeby xmflea Tags: acceleration, distance, force, time 

#1
Oct108, 01:20 PM

P: 44

A dockworker applies a constant horizontal force of 89.0N to a block of ice on a smooth horizontal floor. The frictional force is negligible. The block starts from rest and moves a distance 12.5m in a time 5.10s .
A)What is the mass of the block of ice? B)If the worker stops pushing at the end of 5.10s , how far does the block move in the next 5.30s ? 2. Relevant equations: F=ma 3. The attempt at a solution: well i was able to solve part A by using the equation deltaD=(v1+v2)/deltaT to find v2. and then i used a=(v2v1)/deltaT and plugged it into F=ma to find the mass. For part B, i tried using the same equation for finding distance, however it could not be done cause i do not know how to find v2, and if i plug in 0 as v2, i get a wrong answer. so basically i need help in solving part B of this problem. thanks. 



#2
Oct108, 01:27 PM

HW Helper
P: 5,346

Don't you want to consider the relationship between x, a, and t? x= 1/ 2 * a * t^{2} If you find a, then F = ma gives you the mass as I think you already know. Part b can be determined by finding the V from V^{2} = 2*a*x That times t gives you distance. 



#3
Oct108, 01:42 PM

P: 44

you mean V^2=2 x .96 x 12.5? that gives me V=4.9, which i already had to use for part A. and if i do 4.9 x 0.2s. i get .98m, which is not the right distance




#4
Oct108, 01:48 PM

P: 44

Finding distance using force, acceleration, time
oh wait nvm, i was reading the question wrong, i thought it was asking what the distance was after 5.3 seconds from 5.1 seconds. i didnt know it meant it was asking the distance after 5.3 MORE seconds. thanks, i got the right answer now.



Register to reply 
Related Discussions  
finding the distance, once you have acceleration and time  Introductory Physics Homework  10  
finding acceleration and time in force problems  Introductory Physics Homework  8  
Finding distance with known constant acceleration  Introductory Physics Homework  3  
finding velocity with changing distance and acceleration  Introductory Physics Homework  4 