The velocity of the `CM` of a system changes from `vec v_1 = 4 hat im//s to vecv_2 = 3 hatj m//s` during time `Deltat = 2 s`. If the mass of the system is `m = 10 kg`, the constant force acting on the system is :

Options

A. 25 N
B. 20 N
C. 50 N
D. 5 N

Answer

A

Explanation

(a) `vec F = m(Delta vec v_(cm))/(Deltat) =(10(3 hat j - 4 hat i))/(2) = 5(3 hat j - 4 hati)`
`|vec F| = 5 sqrt(3^2 + 4^2) = 25 N`.