Doug needs to change the <em>exercises </em>he is doing. Your body begins to become accustomed to what you do, and if you do the same thing every single time - you will stop making progress, and they'll simply become easy.
However, if you walk into the gym and your body is expecting you to just go over and bench press some, go rock some curls, head over to the squat rack then go home - but instead you start out with some dips, then go do lunges, then attack your triceps instead of biceps, your body will be shocked!
When you change it up, your body will react. The goal is to be comfortable being uncomfortable. Also, one of the most overlooked things in working out is the intensity. If you bring it everything you got and go to the last gut wretching rep, you'll see results.
However, if you just leisurely do things with 4 minute rests in between - you won't see true progress.
Hopefully, this helps! =)
Mass - the answer is mass. Since I need to write a bit more, the answers are not density, weight, gravity, size or anything like that!
Answer:
1.58 W
Explanation:
Since the sound spreads uniformly in all directions, it must be in a form of a circle with radius of 12 m. So the area of the circle is
From the intensity of the sound we can calculate the power at 12 m
Answer: 80 Newton
Explanation:
Initial velocity of ball = +20 m/s.
Final velocity of ball = -20 m/s
Mass of ball = 0.1kg
Time taken = 0.05 seconds
Average force = (Change in momentum of moving ball / Time taken)
Since, change in momentum = Mass (final velocity - initial velocity)
Change in momentum =0.1 x (-20 - (+20))
= 0.1 x (-20-20)
= 0.1 x (-40)
= -4.0 kgm/s
Then, put -4.0 kgm/s in the equation of force when Average Force = (Change in momentum / Time taken)
= (-4.0kgm/s / 0.05 seconds)
= 80Newton (note that the negative sign does not reflect on the magnitude of force)
Thus, the average force exerted on the ball is 80N
