Question

7. A ship weighs 147500 tonnes and a tugboat weighs 14385 tonnes. A trawler weighs
78582 tonnes more than the tugboat. Find the total weight of ship, tugboat and
trawler.
​

Answer 1

Answer:

Step-by-step explanation:

Mass of the trolley, M=200kg

Speed of the trolley, v=36km/h=10m/s

Mass of the boy, m=20kg

Initial momentum of the system of the boy and the trolley

    =(M+m)v  

    =(200+20)×10

    =2200kg m/s

Let v  

′

 be the final velocity of the trolley with respect to the ground.

Final velocity of the boy with respect to the ground  =v  

′

−4

Final momentum =Mv  

′

+m(v  

′

−4)

                            =200v  

′

+20v  

′

−80

From the conservation of linear momentum:

Initial momentum= Final momentum

                 2200=220v  

′

−80

                   ∴ v  

′

=2280/220=10.36m/s

Length of the trolley, l=10m

Speed of the boy, v  

′′

=4m/s  

Time taken by the boy to run, t=10/4=2.5s

∴ Distance moved by the trolley =v  

′′

×t= 10.36×2.5=25.9m