A speed boat moving at a velocity of 25 m/s runs out of gas and drifts to a stop 3 minutes later 100 meters away. What is its rate of deceleration?

1 Answer
Tanish J.
Dec 30, 2015

#0.139 m/s^2#

Explanation:

From Newton's Equations of Motion, we have:

#v=u+at#

where,
#v# is the final velocity of the boat,
#u# is the initial velocity of the boat,
#a# is the acceleration of the boat,
#t# is the time taken by the boat to accelerate/decelerate from #u# to #v#.

Since the boat decelerates from #25 m/s# to a stop (which is #0 m/s#) in 3 minutes (#=3*60=180# seconds, since all units must be from the SI system),

#u=25 m/s#

#v=0 m/s#

#t=180 s#

Substituting these values in the above equation, we have:

#0=25+a*180#

#-25=a*180#

#a=-25/180=-0.139 m/s^2#

The negative sign indicates that the boat has decelerated. We can simply write that deceleration is equal to #0.139 m/s^2#

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