1) Since the truck is moving, it has kintic energy. The formula for calculating kinetic energy is expressed as
KE = 1/2mv^2
where
m = mass
v = velocity
From the information given,
m = 60000
v = 27
Thus,
Kinetic energy = 1/2 x 60000 x 27^2 = 21870000 J
The amount of work that must be done to stop the truck must be equal to or greater than the kinetic energy. Thus,
amount of work that must be done to stop the truck = 21870000 J
2) Net force applied = - 300000 N
Recall,
Net Force = mass x acceleration
acceleration = net force/mass
acceleration of the truck = - 300000 /60000 = - 5 m/s^2
Since the acceleration is negative, it is decelerating.
To find the distance before it stops, we would apply one of Newton's formula of motion which is expressed as
v^2 = u^2 + 2as
where
v = final velocity
u = initial velocity
a = acceleration
s = distance
From the information given,
v = 0(becuase it will stop moving)
u = 27
a = - 5
By substituting these values into the formula,
0^2 = 27^2 - 2 x 5 x s
0 = 729 - 10s
10s = 729
s = 729/10
s = 72.9
The truck will move 72.9 meters before stopping