A mass of 10 grams and velocity of 9 centimeters per second has a kinetic energy of _____ergs.

Question

Kinetic energy varies jointly as the mass and the square of the velocity. A mass of 15 grams and velocity of 7 centimeters per second has a kinetic energy of 147 ergs. Find the kinetic energy for a mass of 10 grams and velocity of 9 centimeters per second.

Answer 1

1 erg = 1 gram cm²/s²

 

The information given in the problem statement is wrong.  A mass of 15 grams and velocity of 7 cm/s has a kinetic energy of

 

E = mv²/2 = (15 grams)(7 cm/s)²/2 = 367.5 ergs

 

Where did this information come from?

 

A mass of 10 grams and velocity of 9 cm/s has a kinetic energy of

 

E = mv²/2 = (10 grams)(9 cm/s)²/2 = 405 ergs