Question

A gardener holds a hosepipe through which water is gushing out at a rate of $4{\text{kg s}}^{-1}$ with speed $2{\text{ms}}^{-1}$. The moment the speed of water is increased to $3{\text{ms}}^{-1}$, the gardener will experience a jerk of:

• A. $20Ns$ in backward direction
• B. $18Ns$ in forward direction
• C. $10Ns$ in backward direction
• D. $10Ns$ in forward direction

Answer 1

The correct option is A $20Ns$ in backward direction

$F=\frac{dm}{dt}\left(\Delta v\right)=4\times (2+3)=20N$