1). The little projectile is affected by friction all the way through the block.
Friction robs some kinetic energy.
2). The block is affected by friction as it scrapes along the top of the post.
Friction robs some kinetic energy.
3). The block is also affected by friction with the air (air resistance) as it
falls to the ground. Friction robs some kinetic energy.
Answer:
(a) 
(b) 5220 j
(c) 1740 watt
(d) 3446.66 watt
Explanation:
We have given mass m = 290 kg
Initial velocity u = 0 m/sec
Final velocity v = 6 m/sec
Time t = 3 sec
From first equation of motion
v = u+at
So 
(a) We know that force is given by
F = ma
So force will be 
(b) From second equation of motion we know that
We know that work done is given by
W = F s = 580×9 =5220 j
(c) Time is given as t = 3 sec
We know that power is given as
(d) Time t = 1.5 sec
So 
That ratio is called"efficiency". It doesn't need to be a percent.
It can just as well be a fraction or a decimal number.
Answer:
Nuclear energy is that released by dividing the nuclei of heavy atoms (also called under the name Nuclear Fission)
Explanation:
In this process, a large amount of heat is generated that can be used to obtain mechanical energy, which is used to generate electrical energy.
Nuclear energy is a sustainable source of energy having a low impact on the environment.
