To stop the car it would be 100m because if the car is going to 65km/h then it would still be 100km/h
Answer:
23
21.7391304348 m
Explanation:
L = Initial length = 500 m
= Change in temperature = 40-(-35)
= Coefficient of thermal expansion = 
Change in length is given by

The change in length is 0.45 m
The number of joints would be

The number of joints is 23
Each bridge section length would be

The length of each bridge section would be 21.7391304348 m
It's dependent on the mass. You can fimd the force needed using the formula F = ma. Where F is force, m is mass of the cart and a is the acceleration (0.9m/s^2). The heavier it is the more force you are going to need. Remember unit of force is N