Question

The kinetic energy k of an object in joules is given by the formula k= 1 over 2mv^2 where m is the object’s mass in kilograms and v is it’s velocity in meters per second. An object’s velocity in meters per second, and it’s kinetic energy is 48,000 joules..If it speeds up to 40 meters per second, what is its new kinetic energy

Answer 1

Ek = 192000 [J]

Step-by-step explanation:

Originally missing speed data to solve this problem, we must assume that the original speed is 20 [m/s]. In this way, we can calculate the mass of the object.

48000 = (1/2)*m*(20)^2

m = 240 [kg]

The mass is conserved since it does not change only changes the speed of the body so we can calculate a new kinetic energy.

Ek = (1/2)*240*(40)^2

Ek = 192000 [J]