Answer:
180 W
Explanation:
The work done by the man against gravity is equal to its gain in gravitational potential energy:

where
(mg) = 720 N is the weight of the man
is the change in height
Substituting,

The power he must deliver is given by

where
W = 3600 J
t = 20 s is the time taken
Substituting,

Energy is released in the reaction
Explanation:
In a given where the energy of the products is greater than that of the reactants, we can infer that energy is released in the reaction.
This indicates that the reaction is an exothermic or exergonic reaction.
These reaction types are accompanied by release of energy.
- In an exothermic change energy is released to the surroundings.
- The surrounding becomes hotter at the end of the change.
- This applies in exergonic reaction which leaves a reaction having more energy than it originally started with.
Learn more:
Exothermic process brainly.com/question/10567109
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This causes the fluid to increase its speed. Bernoulli's principle tells us that an increase in the speed of a fluid happens at the same time with a reduction in pressure or a reduction in the fluid's potential energy. This necessitates that the amount of kinetic energy, potential energy and internal energy stays persistent.
The mass of the car is 2000 kg
Explanation:
We can solve this problem by using Newton's second law of motion, which states that the net force acting on an object is equal to the product between the mass of the object and its acceleration:

where
is the net force
m is the mass
a is the acceleration
In this problem, we have:
is the acceleration of the car
Each person applies a force of 400 N, and there are five men, so the total force applied is

Therefore, the mass of the car is:

Learn more about Newton's second law of motion:
brainly.com/question/3820012
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