In order to determine the mass of the car, you first calculate the acceleration of the car, by using the following formula:
[tex]a=\frac{v_2-v_1}{\Delta t}[/tex]where:
v2: final speed of the car = 2.8 m/s
v1: initial speed of the car = 1 m/s
Δt: time interval = 12 s
You replace the previoues values into th formula for the acceleration:
[tex]a=\frac{2.8m/s-1.0m/s}{12s}=0.15\frac{m}{s^2}[/tex]Next, you the Newton's second law to find the mass of the car. You proceed as follow;
[tex]F=ma[/tex]where:
m: mass of the car = ?
a: acceleration of the car = 0.15m/s²
F: force exerted on the car by the man = 127.5N
You solve for m in the formula for F, and you replace the values of the other parameters to obtain m, just as follow:
[tex]m=\frac{F}{a}=\frac{127.5N}{0.15m/s^2}=850\operatorname{kg}[/tex]Hence, the mass of the car is 850kg
