An underwater research rover (ROV) is being winched upwards towards a recovery ship. As it nears the surface, it decelerates.
Calculate the time taken for the vertical velocity of the ROV to decrease from 3.5 m/s to 1.1 m/s. Use the equation:
$$
\text{time taken} = \frac{\text{change in velocity}}{\text{deceleration}}
$$
Calculate the magnitude of the resultant vertical force acting on the ROV to cause this deceleration. Use the equation:
$$
\text{resultant force} = \text{mass} \times \text{deceleration}
$$