Answer:
It takes 
to accelerate the object from rest to the speed v.
Explanation:
From Newton's second law:
(1)
and the definition of acceleration,
(2)
we can solve this problem. Putting (2) in (1) we have:
and solving for 
and considering the initial time as zero (
) and the initial velocity also zero (
) we have:
Now, for a mass 
and the 
we can wrtie the same equation:
and substituting 
and 
:
So now, it only takes half the time to accelerate the object from rest to the speed v
The work done on the car is -20 J.
Work done on the car is negative, meaning that the car actually does work on the external system.
<h3>Energy and law of conservation of energy</h3>
- Energy is the ability to do work
- the law of conservation of energy states that the total energy in a system is conserved
From the law of conservation of energy, the initial energy of the car before it moves down the road remains constant or unchanged.
- Initial energy = 100 J
- Initial energy = Final energy - work done on car
- Final Energy = Work done on car + initial energy
80J = Work done on car + 100 J
Work done on car = 80 - 100J
Work done on car = -20 J
Hence, the work done on the car is -20 J
Work done on car is negative.
Since work done on the car is negative, it means that the car actually does work on the external system. Hence, the decrease in the energy of the car.
Learn more about energy and work at: brainly.com/question/13387946
It’s C
Because C is a reflection which reflects something such as mirror
Hope this helps! •~•
Answer:Eating. Your muscles in your arms and mouth use energy to feed itself. Then your body digest the food which also takes energy.
Sleep. When your tired, you don’t have much energy. It is said that you use more energy while your sleeping. But how do you become energized if you were using even more energy than before?
If f=140hz
speed=?
wavelength=?
without all information given, it would be difficult to answer but the formula is speed=frequency ×wavelength
