Compare the kinetic energy of a 20,000-kg truck moving at 110 km/h with that of an 80.0-kg astronaut in orbit moving at 27,500 km/h. For this Practice Exam question, calculate the kinetic energy of the astronaut.

The kinetic energy of the astronaut is far greater than that of the truck; 2,334,111,728.4Joules

Explanation:

Given the mass of the truck to be 20000kg and its velocity to be 110km/hr, its velocity in meter/seconds will give;

110*1000m/1*3600s

= 110000m/3600s

= 30.6m/s

KE of the truck = 1/2MV²

= 1/2*20000*30.6²

KE = 9,363,600Joules

KE of truck = 9.363MJ

Similarly, given mass of the astronaut to be 80kg and velocity of 27500km/hr, converting the velocity to m/s we have:

27500*1000m/1*3600s

= 27,500,000/3600

= 7638.9m/s

Its kinetic energy will be;

KE = 1/2*80*7638.9²

KE = 2,334,111,728.4Joules

KE = 2.33GJ

The kinetic energy of the astronaut is approximately 2.33gigaJoules

This shows that the kinetic energy of the astronaut is far greater than that of the truck.