A force ` (2hat I + hat j - hat k)N` acts on a body which is initially at rest. At the end of 20 sec the velocity of the body is `(4 hat i + 2 hat j – 2 hat k) ms^(-1)`,then mass of the body is

Explanation

Force , F = 2i + j - k
time , t = 20
Initial velocity , u = 0
Final velocity ,v = 4i + 2j - 2k = 2 (2i + j - k )
Acceleration , a `=(v = u )/(t)`
`= (2(2i + j - k) - 0 )/(20) = (2i + j - k) /(10)`
Mass of the body, m `=(f)/(a)`
`= (2i + j - k )/((2i + j - k) // 10) = 10 g `