ENERGY QUESTION 2

Question

A ship of mass 125 MT accelerates at 220 m/s^2 from an initial speed of 10 knots. a) How fast will the ship be travelling after 45 min. b) How much kinetic Energy has the ship gained?

Answer 1

1 MT = 1000 kg therefore 125 MT = 125,000 kg

1 knot = 0.51444 m/s therefore 10 knots = 5.1444 m/s

1 min = 60 sec therefore 45 min = 2700 sec

Using the kinematic equation of motion for constant acceleration:

v_f = v_i + at then

v_f = 5.1444 + 220(2700) = 594,000 m/s (not a very realistic problem is it?)

Initial Kinetic Energy: 1/2(125,000)(5.1444)² = 1654053 j

Final Kinetic Energy: 1/2(125,000)(594005)² = 2.21 x 10¹⁶ j

Amount gained = 2.21 x 10¹⁶ j - 1654053 j = 2.21 x 10¹⁶ j