Answer:
A) m = 1600 kg , B) p = 3.2 10⁴ kg m / s , C) Δp = - 3.2 10⁴ kg m / s
D) t = 51.6 s
Explanation:
A) They indicate the weight of the vehicle W = 15680 N
weight is the attraction of the earth on a body
W = m g
m = W / g
m = 15680 / 9.8
m = 1600 kg
B) The momentum is defined by
p = m v
p = 1600 20
p = 3.2 10⁴ kg m / s
C) the moment change is
Δp = p_{f} -p₀
as the vehicle stops the final speed is zero and therefore the moment is zero
ΔP = 0 - p₀
Δp = - 3.2 10⁴ kg m / s
D) Let's use Newton's second law
F = m a
a = F / m
a = 6.2 102/1600
a = 0.3875 m / s²
Now we can use kinematics, note that as the vehicle stops, the relationship must be opposite to the speed
v = v₀ - a t
v = 0
0 = v₀ - a t
t = v₀ / a
t = 20 / 0.3875
t = 51.6 s
