Answer:
Work done, W = 1.44 kJ
Explanation:
Given that,
Mass of boy, m = 74 kg
Initial speed of boy, u = 1.6 m/s
The boy then drops through a height of 1.56 m
Final speed of boy, v = 8.5 m/s
To find,
Non-conservative work was done on the boy.
Solution,
The work done by the non conservative forces is equal to the sum of total change in kinetic energy and total change in potential energy.
W = 1447.21 Joules
or
W = 1.44 kJ
Therefore, the non conservative work done on the boy is 1.44 kJ.
While travelling along a highway a drivers velocity is 9 m/s. In 12 seconds, the car has gone for 108 m.
<u>Explanation:</u>
The car travelling along the highway has a uniform velocity of 9 m/s. therefore to calculate the distance travelled by the car with the uniform velocity in 12 seconds, simple formula of velocity is to be employed.
Thereby, as we know that
The displacement is along the highway with uniform motion, therefore, distance=displacement
Given that,
Velocity = 9 m/s
Time = 12 s
Putting the values in the formula, we get,
Therefore, the car travels for 108 m in the 12 seconds while travelling along highway with 9 m/s of velocity.