Question

A body of mass m = 10^-2kg is moving in a medium and experiences a frictional force F = - kv^2. Its initial speed is v_o =10 ms^-1 If after 10 s, its energy is 1/8mv²_0, the value of k will be

(a) 10^-3 kgs^-1

(b) 10^-4 kgm^-1

(c) 10^-1 kgm^-1 s^-1

(d) 10^-3 kgm^-1

Answer 1

Correct option (b) 10^-4 kgm^-1
 Explanation:

Given,  force F = -kv²

Now, with limits, we have