Answer:

Explanation:
First we have to find the time required for train to travel 60 meters and impact the car, this is an uniform linear motion:

The reaction time of the driver before starting to accelerate was 0.50 seconds. So, remaining time for driver is 1.5 seconds.
Now, we have to calculate the distance traveled for the driver in this 0.5 seconds before he start to accelerate. Again, is an uniform linear motion:

The driver cover 10 meters in this 0.5 seconds. So, the remaining distance to be cover in 1.5 seconds by the driver are 35 meters. We calculate the minimum acceleration required by the car in order to cross the tracks before the train arrive, Since this is an uniformly accelerated motion, we use the following equation:

Answer:
Thus, the payback time for cavity wall insulation is 7.5 years
Answer:
It will take 8.80 sec to fall from the building
Explanation:
We have given height pf the state building h = 380 m
Initial velocity will be 0 m /sec
So u = 0 m/sec
Acceleration due to gravity 
We have to find the fall time
According to second equation of motion 
So 

t = 8.80 sec
Answer: 1.76 Nm
Explanation:
If the force pulls horizontally, this means that the force is tangent to the disk at any point of the string unwinding process, so the distance d is irrelevant.
In this case, the torque is directly given by the product of the force times the distance perpendicular to the center of the disk, which is just the radius, as follows:
τ = F * r = 16 N. (0.11) m = 1.76 Nm