The answer would be a.
a chemical change is a change to the chemical makeup of a substance so if the bonds are unchanged it would be a characteristic of a physical change
Answer:
Light shone on metal expulses electrons from its surface. This phenomenon is the photoelectric effect, and the electrons are called photoelectrons. Experiments indicate that by increasing light frequency, the kinetic energy of the photoelectrons increases, and by intensifying the light, the current increases
Answer:
he will use kinetic energy to break through the door
Explanation:
because kinetic energy is movement and force
Answer: The volume of gas expands because of the decrease in pressure as he tries to exit the water body, therefore he must take necessary precaution.
Explanation:
Using Boyle's law which states that the the pressure of a given mass of an ideal gas is inversely proportional to its volume at a constant temperature
ie P1VI=P2V2
A diver absorbs compressed nitrogen gas when he dives into the water body, As he ascends out of the water body having less pressure, the volume of nitrogen gas which he absorbs will tend to expand following Boyle's Law. Therefore a scuba driver should not rises quickly but slowly to the surface or else the expanding nitrogen gas can cause tiny bubbles in his blood and tissue to form together with joints pains and eventually cause decompression sickness needing medical attention.
Answer:
5.886 J
Explanation:
Given:
The mass of the book is, 
kg
Height of lift is, 
m
Acceleration due to gravity is, 
m/s²
Now, gain in gravitational potential energy is a function of change in position and is given as:
Here, 
is the change in gravitational potential energy.
Plug in 0.5 kg for 
, 9.81 for 
and 1.2 for 
. Solve for
Therefore, the gain in gravitational energy of the book is 5.886 J.
