An ideal machine is one in which no part of the input energy to the machine gets wasted and the whole input energy is converted into the useful work. The <span>efficiency of such a machine is 100%.
i really hope this helps!</span>
Answer:
The K.E of the bowling ball right before it hits the ground, K.E = 2450 J
Explanation:
Given data,
The mass of the bowling ball, m = 10 kg
The height of the building, h = 25 m
The total mechanical energy of the body is given by,
E = P.E + K.E
At height 'h' the P.E is maximum and the K.E is zero,
According to the law of conservation of energy, the K.E at the ground before hitting the ground is equal to the P.E at 'h'
Therefore, P.E at 'h'
P.E = mgh
= 10 x 9.8 x 25
= 2450 J
Hence, the K.E of the bowling ball right before it hits the ground, K.E = 2450 J
Answer:
(a) 
(b)
Explanation:
Given that , the power of the laser beam is,

and time is given is,

Now the energy formula for the laser beam is,

Now,
(a) The value of energy is given,

Now the no of photons's fraction fluctuation is,

Therefore the no of photons is
.
(b)The value of energy is given,

Now the no of photons's fraction fluctuation is,

Therefore the no of photons is
.
Answer:
The distance covered by puck A before collision is 
Explanation:
From the question we are told that
The label on the two hockey pucks is A and B
The distance between the two hockey pucks is D 18.0 m
The speed of puck A is 
The speed of puck B is 
The distance covered by puck A is mathematically represented as

=> 
The distance covered by puck B is mathematically represented as

=> 
Since the time take before collision is the same

substituting values

=> 
=> 
Stars are located at a distance which are measured in terms of light years. Light year is an Astronomical unit used to measure distance between distant Celestial bodies.
1 light year = 9460730472580<span>800 metres
But no star is located at a distance of 1 light year. Some stars are located at millions of light years and light travels ~ 3 x 10</span>⁸ m/s. Thus light takes time to reach our atmosphere.