Answer:
t = 300.3 seconds
Explanation:
Given that,
The mass of a freight train, 
Force applied on the tracks, 
Initial speed, u = 0
Final speed, v = 80 km/h = 22.3 m/s
We need to find the time taken by it to increase the speed of the train from rest.
The force acting on it is given by :
F = ma
or

So, the required time is 300.3 seconds.
Three forces involved in brushing your teeth are first push, then pull, then push.
Answer:
Nuclear fusion
Explanation:
In fusion, many nuclei (the centers of atoms) combine together to make a larger one (which is a different element). ... A star's mass determines what other type of nucleosynthesis occurs in its core (or during explosive changes in its life cycle).
Explanation :
(1) Involuntary muscles are the muscles that are not controlled by our will.
(2) Tendons are the connective tissues that join the muscle to bones. Tendons are tissues that have fibers.
(3) Cardiac muscle is also involuntary muscles. For example heart muscle. It shows contraction and relaxation throughout life.
(4) Voluntary muscle is the muscles that are not controlled by our will.
(5) Biceps are the arm muscles.
Hence, this the required explanation as per options.
Answer:
power output/transformer efficiency multiply by 100%
Explanation:
derrive the formula from efficiency=power output/power input multiply by 100%