Answer:
W = 1250 J = 1.25 KJ
Explanation:
The work done by the boy is due to the change in the position of the cement vertically. Hence, the work done in this case will be equal to the potential energy of the cement:

where,
W = Work done = ?
mg = W = weight of cement = 500 N
h = height covered = 2.5 m
Therefore,

<u>W = 1250 J = 1.25 KJ</u>
Answer:
a. Final velocity, V = 2.179 m/s.
b. Final velocity, V = 7.071 m/s.
Explanation:
<u>Given the following data;</u>
Acceleration = 0.500m/s²
a. To find the velocity of the boat after it has traveled 4.75 m
Since it started from rest, initial velocity is equal to 0m/s.
Now, we would use the third equation of motion to find the final velocity.
Where;
- V represents the final velocity measured in meter per seconds.
- U represents the initial velocity measured in meter per seconds.
- a represents acceleration measured in meters per seconds square.
- S represents the displacement measured in meters.
Substituting into the equation, we have;


Taking the square root, we have;

<em>Final velocity, V = 2.179 m/s.</em>
b. To find the velocity if the boat has traveled 50 m.


Taking the square root, we have;

<em>Final velocity, V = 7.071 m/s.</em>