What has more kinetic energy a 0.0018-kg bullet traveling at 402 ms or a 6.8 107-kg ocean liner traveling at 10 ms 19 knots?

Answer 1

For an object of mass m (measured in kilograms, kg) travelling at a speed v (measured in metres per second, m s-1), assuming that v is well below the speed of light, the kinetic energy E (measured in joules, J) is given by:

E = 1/2 m v2

So for the bullet, m = 0.0018 kg, and v = 402 m s-1:

E = 1/2 x 0.0018 kg x (402 m s-1)2

= 145.4436 J

For the ocean liner, assuming m = 6.8 x 107 kg (68 000 000 kg), and v = 10 m s-1:

E = 1/2 x 68 000 000 kg x (10 m s-1)2

= 3 400 000 000 J

So the bullet has a kinetic energy of around 145 joules, and the ocean liner has a kinetic energy of 3.4 billion joules. To answer the question, the ocean liner has more kinetic energy than the bullet.