In a particle accelerator, you accelerate an electron. Afterwards, you measure it's energy to be 350 keV. Tell my why you can't find the speed from this energy using your knowledge of classical mechanics.
In order to see what the problem is, I will attempt to find this speed. 350keV=5.6110-14 J Ek=1/2 * mv2 => v=sqrt(2Ek/m) By plugging in numbers, we find that the velocity of the electron, v=3.51108. This velocity is bigger then the speed of light c=3108, and it is a known fact that nothing can travel faster than light. This means that relativistic effects must've taken place, which prevented the particle from reaching the speed of light, but allowed it to have such a high energy.
CP
Related Physics A Level answers
All answers ▸Calculate the time taken for 1000L of water at rtp to be heated to 40degrees celsius using a 40kW heater
Why is an object moving in a circle at a constant speed said to be accelerating?
A ball is hit horizontally at a height of 1.2 m and travels a horizontal distance of 5.0 m before reaching the ground. The ball is at rest when hit. Calculate the initial horizontal velocity given to the ball when it was hit.
A ball is launched upwards at 30 degrees to horizontal with a velocity of 20 metres per second, how far does it travel before landing? (no air resistance)