Physics

Energy

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Kinematics

# If a 20-kg mass has a kinetic energy of 810 Joules after falling a certain distance what is the speed of the object?

###### Wiki User

###### February 21, 2010 11:38AM

## Kinetic energy

The formula for kinetic energy, Ek, could not be simpler.

Ek = (1/2)mv2, where m is mass (in kg) and v is velocity (in m s-1). If you prefer, you could write Ek = mv2/2.

or, 810j=1/2*20Kg*v2

or,v2=810j*2/20Kg

or,v=sqrt of 81

so,v=9m s-1

## Related Questions

###### Asked in Physics

### When an object falls which energy changes to?

As the object falls, it PEG or potential gravitational energy
becomes kinetic energy. Before falling, it has for example 10
joules of PEG and 0 joules of Kinetic energy. As it falls, the PEG
decreases and the kinetic energy increases, until it hits the
ground, when all the energy is dispersed as sound, heat, etc.