D) compounds and pure substances
because none of them are elements
Answer:
d
Explanation:
you record it during the test
85 decibels or higher can cause damage to the human ear.
Decibels is the value of the measurement of sound. Hearing loss can be caused
by noise coming from a loud sound. Noise induced hearing loss maybe permanent
loss or temporary loss. Examples of activities that can give you a noise induced
hearing loss is target shooting, listening to music in your earphones that have
a high volume, and using lawnmowers.
This is weird.
All three 'choices' are true.
Line um up. (a) shows how to solve the problem. (b) does it. and (c) is the answer.
Answer:
the work converted to thermal energy is 40 J.
Explanation:
Given;
work done by the physicist,w = 100 J
height through which the book is raised, h = 0.2 m
efficiency of machine = 60% = 0.6
The useful work done by the machine is calculated as;
useful work = 0.6 x 100 = 60 J
The wasted energy = 100 J - 60 J
The wasted energy = 40 J
The wasted energy by the machine is possibly converted to thermal energy by the frictional part of the machine.
Therefore, the work converted to thermal energy is 40 J.