Angie+Alegre

i) In order to find the distance the cab goes at its maximum speed, the distance in m/s should be calculated.
 * Week 01.**

After the velocity has the units m/s, the acceleration is also given and the final displacement is given. I will assume that the starting point was at zero. In order to find the total distance the car moved at max speed, I would use the formula v^2=(Vo)^2+2*a*(X-Xo). This will give me the distance it travelled at max speed.

ii) Since the velocity is not constant. It is important to find the time it takes for the cab to complete the 190 m. In order to do, I will use the formula X-Xo =Vo*t + (1/2)*a*t^2. This equation does not use the final velocity, it is only affected by the acceleration and the distance. Since it is does not stop, it is safe to assume that the acceleration remains constant. carefully check the solution posted on my page

02. i) In this problem, the final displacement and acceleration is given. Since the rock is being dropped, it is evident that the initial velocity is 0 m/s and the initial displacement is 0 m. In order to find out how long the rocks take to reach the surface, the formula X-Xo=Vo*t+(1/2)*a*t^2. This equation will give me the time in seconds on how long it takes the rock to hit the water.

ii) Since the object is being thrown there is an initial velocity, which is not known. You only know that the final velocity is 0 ( **NOTE : FINAL VELOCITY IS NOT zero** ), the acceleration remains 9.81 m/s^2 and the time is 3.19-1s= 2.19s. In order to find the initial velocity, the formula V=Vo+a*t will be used.

Professor's Note : Good work !! exactly what I expected -- check my page to correct the error you made in the second problem

03. i)  Given:  Ai + Bi = 6i  Ai - Bi = -4i
 * Week 02**

Using guess and check method by addition and subtraction to find numbers that will satisfy both equation.

Given: Aj + Bj = 1i Aj - Bj = 7j Using guess and check method by addition and subtraction to find numbers that will satisfy both equation.

ii)In order to find the magnitude I use the formula a=(Ax^2+Ay^2)^1/2, the same equations is applied to find B. iii) To find it, you need to use the equation that gives you the components, then I multiply the two components and add them. Then I can divide the quantity by the magnitudes. Finally use the inverse function of cosine to find the final result.


 * Check my page for the complete solution - professor**

__**Week four (13 th February, 2012)**__ 1. A 0.5 kg rock is projected from the edge of the top of a building with an initial velocity of 10.5 m/s at an angle 54º above the horizontal. Due to gravity, the rock strikes the ground at a horizontal distance of 15.3 m from the base of the building. Assume: The ground is level and that the side of the building is vertical. The acceleration of gravity is 9.8 m/s². What is the height of the building?

In order to find the height of the building two different equations must be used. Since the object is dropped vertically, it is evident there is no horizontal acceleration, thus using the equation X-X0=(Vo*cos(54)*t) will give the time, the rock takes to reach the floor.

Once the time is found, the formula Y-Yo=Vo*t-(1/2)*g*t^2 will be used. The gravity of the dropped is given and the initial velocity will be the velocity which is 10.5 times sin(54). Once all the values are plugged in, the initial displacement(height of building) will be solved. ---

No new work was found -- Professor