Work And Energy 8

Question

If a projectile with a mass of 9.90 g is traveling at a speed of 1.23 km/s, determine the following.
(a) kinetic energy of the projectile in kilojoules

 

kJ

 

(b) kinetic energy of the projectile in kilojoules, if its speed is reduced by a factor of two

kJ

 

(c) kinetic energy of the projectile in kilojoules, if its original speed is increased by a factor of three

 

kJ

Answer 1

Hi Dominic!

 

Kinetic energy (KE) = (1/2)mv²

 

where m = mass and v = speed.  This gives you the kinetic energy in joules, which you can convert to kilojoules in the same way grams are converted to kilograms.