Dear PF Forum, I have a problem with calculating energy which I should have learnt long ago in my high school time. If I push (accelerate) a 1 kg object 1 meter/sec2 for 10 seconds, I spend energy like this. Distance = 1/2 at2. So I would have pushed this object for 50 metres. So I'm using energy 50 metres * 1 kg * 1 m/sec2 = 50 joules. Am I right? Now for the second question. Supposed I push a wall with the same force as above for 10 seconds, how can I calculate the energy consumption? Considering the wall doesn't move. Thank you very much.