I have three problems that have stumped me. I attempted to utilize the equations my teacher said we'd be using but I don't know where I went wrong or what each equation is specifically for (e.g. finding displacement in constant acceleration or whatnot). Am I using the equations correctly? :uhh: 1st Problem: A car accelerates from rest at a constant rate of 2.0 m/s^2 for 5.0s. A) What is the speed of the car at that time? B) How far does the car travel in this time? My workings: x = Vot + 1/2at^2 x = 0(5.0s) + 1/2(2.0 m/s^2)(5.0s)^2 = 0 + 1/2(2.0 m/s^2)(25.0 s^2) = 50 m/s^4/2 = 25 m/s^4 2nd Problem: A bullet traveling horizontally at a speed of 350 m/s hits a board perpendicular to the surface, passed through it, and emerges on the other side at a speed of 210 m/s. If the board is 4.00 cm thick, how long does the bullet take to pass through it? My workings: I know that Vo or Vi is 350 m/s, A is 4.00 cm, Vf is 210 m/s but how do I convert the negative acceleration factor, A, into a speed? I also have no clue as to which equation to use for this. 3rd Problem: Two identical cars capable of accelerating at 3.00 m/s^2 are racing on a straight track and cross the starting line together with running starts. Car A has an initial speed of 2.50 m/s; car B starts with an initial speed of 5.00 m/s. A) What is the separation of the two cars after 10 m/s. B) Which car is moving faster after 10 s? My workings: By the separation of the two cars, do they mean displacement? I don't know where to proceed. So far.. A - 3.00 m/s^2 (I'm not sure of this as the problem used the word "capable") Vo (A) - 2.5 m/s Vo (B) - 5.00 m/s T - 10 s Vf - ? When I use x=VoT + 1/2at^2 my result ends up with m/s^4. Am I using the wrong equation?