Answer:
(a) The time taken for the plane to reach 50 km/hr is 811.97 s
(b) (i) the acceleration of the plane is 0.012 m/s²
(ii) The time taken for the plane to reach 50 km/hr is 1172.85 s
Explanation:
Given;
mass of the freight train, m = 3.8 x 10⁷ kg
force applied to pull the train, F = 6.5 x 10⁵ N
a. How long does it take the train to go from rest to 50 km/hr?
Given;
initial velocity, u = 0
final velocity, v = 50 km/hr = 13.889 m/s
Apply Newton's second law of motion to determine the time traveled by the train at the given speed;
[tex]F = ma = \frac{m(v-u)}{t}\\\\t = \frac{m(v-u)}{F}\\\\t = \frac{3.8*10^7(13.889-0)}{6.5*10^5}\\\\t = 811.97 \ s[/tex]
(b)
(i) the acceleration of the plane
Given;
air resistance, = 2.0 x 10⁵ N
Apply Newton's second law of motion;
∑F = ma
6.5 x 10⁵ N - 2.0 x 10⁵ N = ma
4.5 x 10⁵ N = ma
[tex]a = \frac{4.5 * 10^5 }{m}\\\\a = \frac{4.5 * 10^5 }{3.8*10^7}\\\\a = 0.012 \ m/s^2[/tex]
(ii) time taken for the plane to reach 50 km/hr is given by;
[tex]F = \frac{m(v-u)}{t}\\\\t = \frac{m(v-u)}{F}\\\\t = \frac{3.8*10^7(13.889-0)}{4.5*10^5}\\\\t = 1172.85 \ s[/tex]
