Answer:
a = - 1.987 × 10⁶ ft/s²
t = 6.84 × 10⁻⁴ s
Explanation:
v₀ = 910 ft/s
x = 5 in.
relation v = v₀ - k x
v = 0 as body comes to rest
0 = 900 - 5k/12
k = 2184 s⁻¹
acceleration

where
(A) a = -k × v
at v= 910 ft/s
a = - 1.987 × 10⁶ ft/s²
(B) at x = 3.9 in.
v = 910 - 3.9(2184)/12
v = 200.2 m/s




t = 6.84 × 10⁻⁴ s
(1,500 meters) x (1 sec/330 meters) =
(1,500 / 330) (meters-sec/meters) =
4.55 seconds
Is is the second one. 336 k. 273.15K= 0C.