Question

An electron moving with a velocity of 5x104 ms-1
enters into a uniform electric field and acquires a
uniform acceleration of 104 ms-2
in the direction of its initial motion.

(i)Calculate the time in which the electron would acquire a velocity double of its initial velocity.

(ii) How much distance the electron would cover in this time?

Answer 1

Explanation:

Given initial velocity, u = 5 × 104 m s-1 and acceleration,

a = 104 m s–2

(i) final velocity = v = 2

u = 2 × 5 ×104 m s–1 =10 × 104 m s–1

To find t, use

v = at or t = u - u / a (ii) Using s = ut + 1/ 2 at 2 = (5 ×104) × 5 + 1/ 2 (10 ) × (5) 2 = 25 ×104 + 25 /2 ×104 = 37.5×104