Yes, you are correct. The answer is b) 2 s.
You found the double derivative (acceleration) of the position function and set it to zero, which is the condition for the net force to be zero (F = ma, and F = 0 when a = 0). From there, you solved for t and found t=2, which corresponds to option b.
The position of a toy locomotive mobing on a straight track along the x-axis is given the equation x=t^3-6t^2 +9t where x is in metters and t is in seconds. The net force on the locomotive is equal to zero when t is eqaul to
a) zero
b)2 s
c)3 s
d)4s
e)5s
Would the answer be b)2 s? I found the double derivative of the equation and set x to 0 and solved for t.
f'= 3t^2 - 12t + 9
f"=6t - 12
yes, t=2
1 answer
1 answer