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.
The water pressure on the first floor must be 455 PSI in order to push the water to the 13th floor at the given pressure.
The given parameters;
- <em>Pressure on the 13 th floor, P₁ = 35 PSI</em>
- <em>Distance between each floor, d = 10 ft</em>
The vertical pressure of the water is calculated as follows;

The vertical height of the first floor from the 13th floor = 130 ft
The vertical height of the 13 ft floor = 10 ft

Thus, the water pressure on the first floor must be 455 PSI in order to push the water to the 13th floor at the given pressure.
Learn more about vertical height and pressure here: brainly.com/question/15691554
For balancing the lever, force on both the sides shall be equal. so,
Force on 3 m end = m × a = 3 × 98.1 = 294.3
Now, on 6 m end, it would be: = 294.3/6 = 49.05
After rounding-off to the nearest hundredth value, it would be: 49 N
Finally, Option A would be your correct answer.
Hope this helps!
Answer:
490N
Explanation:
According Newton's second law!
\sum Force = mass × acceleration
Fm - Ff = ma
Fm is the moving force
Ff s the frictional force = 100N
mass = 65kg
acceleration = 6m/s²
Required
Moving force Fm
Substitute the given force into thr expression and get Fm
Fm -100 = 65(6)
Fm -100 = 390
Fm = 390+100
Fm = 490N
Hence the force that will cause two cart to move is 490N
Answer:
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Explanation: