Answer:
9.43 m/s
Explanation:
First of all, we calculate the final kinetic energy of the car.
According to the work-energy theorem, the work done on the car is equal to its change in kinetic energy:

where
W = -36.733 J is the work done on the car (negative because the car is slowing down, so the work is done in the direction opposite to the motion of the car)
is the final kinetic energy
is the initial kinetic energy
Solving,

Now we can find the final speed of the car by using the formula for kinetic energy

where
m = 661 kg is the mass of the car
v is its final speed
Solving for v, we find

Given data:
* The extension of the steel wire is 0.3 mm.
* The length of the wire is 4 m.
* The area of cross section of wire is,

* The young modulus of the steel is,

Solution:
The young modulus of the steel in terms of the force and extension is,

where F is the force acting on the steel wire,, l is the original length of the wire, dl is the extension of the wire, and A is the area,
Substituting the known values,

Thus, the force which produce the extension of 0.3 mm of the steel wire is 31.5 N.
There is a total of 6 half lives that need to take place.
ONE HALF LIFE = 200
TWO HALF LIFES = 100
THREE HALF LIFES = 50
FOUR HALF LIFES = 25
FIVE HALF LIFES = 12.5
SIX HALF LIFES = 6.25
The answer is 6.25g