The position vector of a particle is vecr=4t^(2)hati+2thatj+3hatk. The speed of the particle t=5s is

The position vector of a particle is vecr=4t^(2)hati+2thatj+3hatk. The

1.	The position vector of a particle is vecr=4t^(2)hati+2thatj+3hatk. The speed of the particle t=5s is
Answer» `42ms^(-1)` 3S `3ms^(-1)` `40ms^(-1)` Solution :`vecr=4t^(2)hati+2thatj+3hatk` SPEED `v=(dvecr)/(dt)=8thati+2hatj` , at t=5s `v=40+2=42`