Answer:
7.9 
Explanation:
Take the fact that mass is inversely proportional to accelertation:
m ∝ a
Therefore m = a, but because we are finding the change in acceleration, we would set our problem up to look more like this:

Using algebra, we can rearrange our equation to find the final acceleration,
:

Before plugging everything in, since you are being asked to find acceleration, you will want to convert 0.85g to m/s^2. To do this, multiply by g, which is equal to 9.8 m/s^2:
0.85g * 9.8
= 8.33
Plug everything in:
7.9
= 
(1590kg the initial weight plus the weight of the added passenger)
Answer:
towards left
Explanation:
As we know that there is no external force on the system of two cart so total momentum of the system is conserved
so we will say

now plug in all data into the above equation

here we assumed that left direction of motion is negative while right direction is positive
so we can solve it for speed v now



Answer:
Collision force will be same in both the cases.
Explanation:
A perfectly inelastic collision is said to take place when a system loses the amount of its Kinetic Energy at its maximum. In a perfectly inelastic collision, the colliding particles stick to each other. In such a collision, kinetic energy is lost by combining the two bodies with each other.
In situation 1:
Speed of Car A, 
Speed of Car B, 
Relative speed of car A and car B, 
Now, in the situation 2:
Speed of car A, 
Speed of car B, 
Relative speed of car A and car B, 
Therefore, Car A and Car B both have the same relative speed, v = 10 m/s