Answer:
a. negative
b. zero
Explanation:
work is the change in the energy of a system due to external forces
work is done when a force moves a load through a distance in the direction of the force
The work done by a force on a system is positive when the force and the force displacement point in the same direction and negative when they point in opposite directions
in the scenario we are considering in the question, the force (the hand) moves the block vertically upwards but the displacement of the block reduces (in the opposite direction) since it decelerates. as such the work done by gravity on the block is negative.
the work done on the block is zero if the system consists of the block and the earth because there is no gravitational force exerted on the system
Answer:
The duck floats on water because his/her density is less than the density of water
Explanation:
Answer:
b. amplitude
Explanation:
An electromagnetic waveconsists of electrical oscillations and magnetic fields. The frequency of the wave is directly proportional to its energy and its speed and inversely proportional to its wavelength. Therefore, with the only magnitude with which it has no relation is with its amplitude.
A. During long jump athlete runs before taking the jump by doing so he provides himself a larger inertia.
<h3>
What is inertia?</h3>
Inertia is the reluctance of an object to stop moving once in motion or start moving when it is at rest.
When an athlete runs before taking the jump, he is trying to increase his inertia, that is his reluctance to stop, thereby increasing his forward motion or jump.
Thus, during long jump athlete runs before taking the jump by doing so he provides himself a larger inertia.
Learn more about inertia here: brainly.com/question/1140505
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Answer:
The pressure at this depth is 
.
Explanation:
According to the statement, the uncompressed fluid stands at atmospheric pressure. By Boyle's Law we have the following expression:
(1)
Where:
- Initial and final volume.
- Initial and final pressure.
If we know that 
, then the pressure ratio is:
If 
, then the final pressure of the gas is:
The pressure at this depth is .
