The initial kinetic energy of the boat and its rider is

After Sam stops it, the final kinetic energy of the boat+rider is

because its final velocity is zero.
For the law of conservation of energy, the work done by Sam is the variation of kinetic energy of the system:

where the negative sign is due to the fact that the force Sam is applying goes against the direction of motion of the boat.
Answer:
Explanation:
Speed given = 125 m /min
125 /60 m /s
In 450 second it will travel
= 450 x 125 / 60
=937.5 m.
As the distance is covered in less than 450 seconds , The distance must be less than 937.5 m
In 400 seconds , it will travel
= 400 x 125 / 60
833.33 m
Since the distance is covered in more than 400 seconds , the distance must be more than ie 833.33 .
Hence the distance covered is more than .833 m but less than 937.5
In either case these distance are more than .8 km .
Linear momentum of a truck is 1,50,000 kg.m/s
Explanation:
Linear momentum is the product of the mass and velocity of an object. It is a vector quantity, which have a magnitude and a direction.
Linear momentum is a property of an object which is in motion with respect to a reference point (i.e. any object changing its position with respect to the reference point).
It's SI units are kg.m/s
Linear momentum is a vector quantity.
Linear momentum formula (p) = mass × velocity
Given data mass = 5000 kg ; velocity = 30 m/s
P = 5000 × 30
Linear momentum p= 1,50,000 kg.m/s
Explanation:
To find the answer use the equation speed of light=wavelength multiplied by frequency (c=lambda*f) by substituting the value for the frequency the the speed of light