Which of the following industries is the largest producer of primary air pollutants in the United States?
1 answer:
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Answer:
20 J
Explanation:
Given:
Weight of the book is,
Height or displacement of the book is,
The work done on the book to raise it to a height of 2 m on a shelf is against gravity. The gravitational force acting on the book is equal to its weight. Now, in order to raise it, an equal amount of force must be applied in the opposite direction.
So, the force applied by me should be equal to weight of the body and in the upward direction. The displacement is also in the upward direction.
Now, work done by the applied force is equal to the product of force applied and displacement of book in the direction of the applied force.
Therefore, work done is given as:
Therefore, the work done to raise a book to a height 2 m from the floor is 20 J.
Answer:
a) 1.89 m/s b) 172.1 N
Explanation:
a)
- Applying the work-energy theorem, if we can neglect the friction between truck and road, the total change in kinetic energy must be equal to the work done by the external forces.
- This work, is just 4,475 J.
- So we can write the following equation:
- where m= mass of the truck = 2.5*10³ kg.
- So, we can find the speed v, as follows:
b)
- The work done by the man, is just the horizontal force applied, times the displacement produced by the force horizontally:
- We can solve for F, as follows: