A projectile of mass 2 kg has velocities 3 m/s and 4 m/s at two points during its flight in the uniform gravitational field of the earth. If these two velocities are perpendicular to each other, then the minimum kinetic energy of the particle during its flight is:

Explanation

`V_(1)cos alpha =V_(2)cos(90-alpha)`
`3cos alpha=4 sin alpha`
`tan alpha =3/4`
`KE_("man") =1/2mv_(1)^(2) cos^(2)alpha`
`1/2 xx 2 xx 3 xx (4/5)^(2) =(9 xx 16)/25 = 5.76` J