A force `vecF=vecvxxvecA` is exerted on a particle in addition to the force of gravity, where `vecv` is the veocity of the particle and `vecA` is a constant vector in the horizontal direction. With what minimum speed a particle of mass m be projected so that it continues to move undeflected with a constant velocity?

Explanation

When the box accelerating upward
` U-mg - (mg)/6`
`gt U=(7mg)/g `

`rarr m= (6U)/7g…i`
`Mg-U=(Mg)/6`
`rarr Mg-(Mg)/6=U`
` rarrM=(6u)/5` ……….ii
`Mass added = (6U)/(5g)- (6U)/(7g)`
` =(6U(7-5)g)/(35g)`
`=(6U.2g)/(35g)`
` From equation i m = (6U)/(7h)`
` :. Added mass = 2/5 mg`