Given:
Sample 1:
Chloroform is 
12 g Carbon
1.01 g Hydrogen
106.4 g Cl
Sample 2:
30.0 g of Carbon
Solution:
mass of chloroform from sample 1:
12 + 1.01 +106.4 =119.41 g
Now, for the total mass of chloroform in sample 2:
mass of chloroform 

mass of chloroform = 119.41 
= 298.53 g
Answer:
The net force on the car is 2560 N.
Explanation:
According to work energy theorem, the amount of work done is equal to the change of kinetic energy by an object. If '
' be the work done on an object to change its kinetic energy from an initial value '
' to the final value '
', then mathematically,

where '
' is the mass of the object and '
' and '
' be the initial and final velocity of the object respectively. If '
' be the net force applied on the car, as per given problem, and '
' is the displacement occurs then we can write,

Given,
.
Equating equations (I) and (II),

Answer:
Yes
Explanation:
Accerelation is measured by change in velocity. So naturally, if an object is slowing down, its velocity is decreasing so acceleration is negative. If it is speeding up velocity is increasing so positive acceleration.
(Velocity final - Velocity initial)/t
Note that this does not apply only to gravity, but to all linear accelerations