Number 1. is incorrect. Calculate the distance traveled while accelerating at 0.1192 m/s^2 and you'll see the car won't cover 2000 meters in 140 seconds. The acceleration needs to be greater, so that the car reaches 60 KPH and cruises at that speed for a certain distance, then decelerates at the end. If we assume that the car comes to a stop at exactly 2000 meters in 140 seconds you can set up two equations like this:

Where v_1 = 60 KPH. Solve for t_1, and then determine a = v_1/t_1

2 is correct

3 is off by a factor ten - the wheel diameter is 0.15m, not 1.5m.

4. The term "g" here means "acceleration of gravity," not grams. The acceleration due to gravity is 9.8m/s^2. So they're asking what the rotation speed must be to generate centripedal acceleration equal to 100,000 x 9.8m/s^2 .