Well, that's a funny first post, but I'll see what I can do.
Draw a free body diagram. Gravity exerts a force down at the centre of mass of the rod, which is in the middle because the rod is uniform.
The pivot point exerts a force up, and the thread exerts a force up.
tau = I * alpha
tau is torque in Nm
I is the rod's moment of inertia in kg*m
alpha is angular acceleration in rad/sec*sec (sec squared)
You're given I in the question. You're looking for alpha. Torque is also given by: tau = rFsin(theta) Since the angle is 90 degrees sin(theta) is 1 and can be ignored.
So you're left with tau = rF. r is the distance from the pivot that force F is applied.
so you have
(l/2)*mg = I * alpha.
Not too sure about this one. Translational acceleration means in a straight line, like drag racers.
If I were desperate I'd just use F = ma but that seems too easy.
I think it's like (a) except the force from the string is no longer there.
Go find your physics textbook and look up "Rotational Motion" It should have something like omega = omega(zero)*t + 0.5*alpha(zero)*t^2.
I believe that's where they key lies.
So, what mods on your car do you have? Surely you didn't join a BMW forum to ask a physics problem.
1987 BMW 325i
1A Offstream Mechanical Engineering / University of Waterloo