B
Think of inertia of getting into a car accident without a seat belt although the car stops you will not you would likely fly out the window
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.
A visual display of data or information is called a graph. There are many types of graphs. These can include pie graphs, bar graphs, and many more. Graphs are useful, because they show you visually data which is helpful to many. Hope this helped
Answer:
15m/s
Explanation:
add the two speeds and divide by 2
10+20=30
30/2=15
Answer:
Cp= 0.44 J/g.C
This is heat capacity of metal.
Explanation:
From energy conservation
Heat lost by metal = Heat gain by water +Heat gain by calorimeter
Because here temperature of metal is high that is why it loose the heat.The temperature of water and calorimeter is low that is why they gain the heat.
final temperature is T= 30.5 C
We know that sensible heat transfer given as
Q= m Cp ΔT
m=Mass
Cp=Specific heat capacity
ΔT=Temperature difference
By putting the values
55 x Cp ( 99.5 - 30.5) = 40 x 4.184 ( 30.5- 21 ) + 10 x ( 30.5 - 21)
Cp ( 99 .5- 30.5) = 30.65
Cp= 0.44 J/g.C
This is heat capacity of metal.