Answer:
a

b
Explanation:
From the question we are told that
The total mass of three people is 
The mass of the car is 
The compression of the car spring is 
Generally the spring constant is mathematically represented as

Here F is the force exerted by the mass of three people and that of the car , this is mathematically represented as
=> 
=> ![F = ([2.0*10^{2} ]+[ 1.200*10^{3}]) * 9.8](https://tex.z-dn.net/?f=F%20%3D%20%28%5B2.0%2A10%5E%7B2%7D%20%5D%2B%5B%201.200%2A10%5E%7B3%7D%5D%29%20%2A%209.8)
=> 
So

=> 
Generally if the mass which the car is loaded with is 
Then the force experienced by the spring is
=> 
=> 
=> 
Generally from the above formula the compression is

=> 
=>
It would be B. Because every angle has to add up to 180 degrees. 180-70 would give you 110
Answer:
a common temperature is reached.
Explanation:
The principle of heat transfer is that heat flows from a substance of higher temperature to that of lower temperature until when a common temperature is reached.
For ice on getting in contact with a hot body; it changes to water at 0°c utilising the latent heat of fusion. After ice has been converted to water at 0°c, water starts increasing in temperature till a common temperature is reached.
Answer:
A. Distance over which the force is applied
Explanation:
As we know that in pulley system the mass of the car is balanced by the tension in the string
so here we will have

so here in order to decrease the force needed to lift the car we have to increase Distance over which the force is applied
So here if we increase the distance over which force is applied then it will reduce the effort applied by us in this pulley system as the torque will be more if the distance is more.
Answer:
The final velocity of the second car is 57 m/s south.
Explanation:
This is an elastic collision between two train cars. In this case, the total kinetic energy between the two bodies will remain the same.
The formula to apply is :

where ;

Given in the question that;

Apply the formula as;

{14650*18}+{3825*11} = {14650 *6} + {3825 * v₂f}
263700+42075=87900 + 3825v₂f
305775 =87900 + 3825v₂f
305775-87900 = 3825v₂f
217875=3825v₂f
217875/3825 =v₂f
56.96 = v₂f
<u>57 m/s = v₂f { nearest whole number}</u>