A block with a mass of 10kg is moving right with velocity 1m/s. I pushed the object leftwards so that its velocity changed to -1m/s.
In this case, the kinetic energy of the block remains constant(5J) before and after the push. Does this mean that no work is done on the block? This feels very strange, as I applied force on the object and caused displacement, just that its direction is opposite. Is there something wrong with this approach?
Here are some points worth considering:
- Kinetic energy is scalar, so the direction the object is moving in doesn’t matter. (Kinetic energy can’t be negative)
- Velocity is vector, so of course my hands did apply a leftward force to the block, which resulted in negative acceleration.