Calculate the speed (in m/s) of an electron and a proton with a kinetic energy of 1.25 electron volt (ev). (the electron and proton masses are me = 9.11 ✕ 10−31 kg and mp = 1.67 ✕ 10−27 kg. boltzmann's constant is kb = 1.38 ✕ 10−23 j/k.)

6.63 x 10⁵ m/s

0.16 x 10⁵ m/s

Explanation:

= mass of the electron = 9.11 x 10⁻³¹ kg

= mass of the proton = 1.67 x 10⁻²⁷ kg

= speed of electron

= speed of proton

= Kinetic energy of electron = 1.25 eV = 1.25 x 1.6 x 10⁻¹⁹ J

Kinetic energy of electron is given as

= 6.63 x 10⁵ m/s

Kinetic energy of proton is given as

= 0.155 x 10⁵ m/s

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.