We will define the Total mass to calculate the force, so our values are:
Total Mass 
The Weight is,
Through the hook's Law we calculate X.
, where x is the lenght of compression and K the Spring constant.
We don't have a K-Spring, but we can assume a random value (or simply let the equation in function of K)
I assume a value of 
Answer:
Temperature after ignition=7883.205 K
Explanation:
The number of moles is,
n=PV/RT
=(1.18x10^6)(47.9x10^-6)/8.314(325)
= 0.0209 moles
a) In this process volume is constant
Q=U
=nCv.dT
dT= Q/nCv
=1970/(1.5x8.314)(0.0209)
= 7558.205 K
The final temperature is,
= 7558.205+325
= 7883.205 K
We can substitute the given values into the equation for T, given the surrounding temperature T0 = 0, initial temperature T1 = 140, constant k = -0.0815, and time t = 15 minutes.
T = 0 + (140 - 0)e^(-0.0815*15) = 140e^(-1.2225) = 41.23°F
It is C) because that truck has more mass
