Spartan029
Sep15-08, 04:41 PM
Hello everyone. Im stumped here with this problem, i feel like it should be fairly simple but i cant seem to figure it out.
1. The problem statement, all variables and given/known data
If the acceleration for a given object is given by the function:
a(t) = +(3 m/s^3) · t
(Note: units are included in the eqn, so if [t]=s then [a]=m/s^2.)
(a) Examining this function, you can tell that:
a1)the size of the acceleration will: ?
a2)the direction of the acceleration will be: ?
(b) If vi (at t=0 s) is -3 m/s, find v(t). Then answer the below:
(b1)the size of the velocity will: ?
(b2)the direction of the velocity will be: ?
(c) If xi (at t=0 s) is -7 m, find x(t). Then answer the below:
c1)After 4 s have passed, What position (x) is the object at now? ___m
c2)What is the total distance travelled (since t=0 s)? ___m
2. Relevant equations
I really dont know, Integration? maybe
3. The attempt at a solution
Okay so for part (a) I answered that the size would be "increasing" which is correct. Also the direction of the acceleration will be "in the + direction" which is aslo correct.
So for part (b) i take the integral of the a(t) and get:
v(t) = (3/2)t^2 - 3 m/s
by examining this i answered that the size would be "increasing" and "in the + direction" both of my answers are wrong and i dont understand why.
Okay so i skip to part (c) take the integral of v(t):
x(t) = (1/2)t^3 - 3t - 7 m
so
x(4) = (1/2)(4^3) - 3(4) - 7 = -11
-11 was not correct. :biggrin: so i thought it wise not to go on to part c2) lol
and here i am stumped. Any help would be much appreciated. Thanks!
1. The problem statement, all variables and given/known data
If the acceleration for a given object is given by the function:
a(t) = +(3 m/s^3) · t
(Note: units are included in the eqn, so if [t]=s then [a]=m/s^2.)
(a) Examining this function, you can tell that:
a1)the size of the acceleration will: ?
a2)the direction of the acceleration will be: ?
(b) If vi (at t=0 s) is -3 m/s, find v(t). Then answer the below:
(b1)the size of the velocity will: ?
(b2)the direction of the velocity will be: ?
(c) If xi (at t=0 s) is -7 m, find x(t). Then answer the below:
c1)After 4 s have passed, What position (x) is the object at now? ___m
c2)What is the total distance travelled (since t=0 s)? ___m
2. Relevant equations
I really dont know, Integration? maybe
3. The attempt at a solution
Okay so for part (a) I answered that the size would be "increasing" which is correct. Also the direction of the acceleration will be "in the + direction" which is aslo correct.
So for part (b) i take the integral of the a(t) and get:
v(t) = (3/2)t^2 - 3 m/s
by examining this i answered that the size would be "increasing" and "in the + direction" both of my answers are wrong and i dont understand why.
Okay so i skip to part (c) take the integral of v(t):
x(t) = (1/2)t^3 - 3t - 7 m
so
x(4) = (1/2)(4^3) - 3(4) - 7 = -11
-11 was not correct. :biggrin: so i thought it wise not to go on to part c2) lol
and here i am stumped. Any help would be much appreciated. Thanks!