Answer:
The work required is -515,872.5 J
Explanation:
Work is defined in physics as the force that is applied to a body to move it from one point to another.
The total work W done on an object to move from one position A to another B is equal to the change in the kinetic energy of the object. That is, work is also defined as the change in the kinetic energy of an object.
Kinetic energy (Ec) depends on the mass and speed of the body. This energy is calculated by the expression:

where kinetic energy is measured in Joules (J), mass in kilograms (kg), and velocity in meters per second (m/s).
The work (W) of this force is equal to the difference between the final value and the initial value of the kinetic energy of the particle:


In this case:
- W=?
- m= 2,145 kg
- v2= 12

- v1= 25

Replacing:

W= -515,872.5 J
<u><em>The work required is -515,872.5 J</em></u>
Answer:
Options d and e
Explanation:
The pendulum which will be set in motion are those which their natural frequency is equal to the frequency of oscillation of the beam.
We can get the length of the pendulums likely to oscillate with the formula;

where g=9.8m/s
ω= 2rad/s to 4rad/sec
when ω= 2rad/sec

L = 2.45m
when ω= 4rad/sec

L = 9.8/16
L=0.6125m
L is between 0.6125m and 2.45m.
This means only pendulum lengths in this range will oscillate.Therefore pendulums with length 0.8m and 1.2m will be strongly set in motion.
Have a great day ahead
Answer:
Option (B) is correct.
Explanation:
Given that the molecules of hydrogen gas (
) react with molecules of oxygen gas (
) in a sealed reaction chamber to produce water (
).
The governing equation for the reaction is

From the given, the only fact that can be observed that 2 moles of
and 1 mole of
reacts to produce 2 moles of
.
As the mass of 1 mole of
grams ... (i)
The mass of 1 mole of
grams ...(ii)
The mass of 1 mole of
grams (iii)
Now, the mass of the reactant = Mass of 2 moles of
+ mass 1 mole of 
[ using equations (i) and (ii)]
grams.
Mass of the product = Mass of 2 moles of 
[ using equations (iii)]
=36 grams
As the mass of reactants = mass of the product.
So, mass is conserved.
Hence, option (B) is correct.
Answer:
Explanation:
Electrical energy is energy derived from electric potential energy or kinetic energy.
Or,
Electrical energy is a form of energy resulting from the flow of electric charge. Lightning, batteries and even electric eels are examples of electrical energy.People use electricity for lighting, heating, cooling, and refrigeration and for operating appliances, computers, electronics, machinery, and public transportation systems.
Hope it helped you.