Muscles function only by contracting. This makes it necessary for one end of the muscle to be fixed and the other mobile.
Take the bicep for example.
Its origin is at the shoulder and its two heads connect to the bones of the forearm, the radius and ulna.
Now, had the muscle not been fixed at one end, and contracted, it would pull both our shoulder and forearm together resulting in an ineffective movement. The desired motion is to lift the forearm (proximal and distal movement) which can only be achieved if the bicep is fixed at the shoulder and allowed to move at the forearm.
Answer:
1.5 m/s²
Explanation:
For the block to move, it must first overcome the static friction.
Fs = N μs
Fs = (45 N) (0.42)
Fs = 18.9 N
This is less than the 36 N applied, so the block will move. Since the block is moving, kinetic friction takes over. To find the block's acceleration, use Newton's second law:
∑F = ma
F − N μk = ma
36 N − (45 N) (0.65) = (45 N / 9.8 m/s²) a
6.75 N = 4.59 kg a
a = 1.47 m/s²
Rounded to two significant figures, the block's acceleration is 1.5 m/s².
Usually the coefficient of static friction is greater than the coefficient of kinetic friction. You might want to double check the problem statement, just to be sure.
Answer: 1608.39 J
Explanation: Given that the
mass M = 42kg
U = 11.5m/s
V = 3.33m/s
how much work did friction do
Work done = Force × distance
Work done = Ma × distance
But acceleration a = V/t
Work done = M × V/t × d
Work done = M × V × d/t
Where d/t = velocity
Therefore,
Work done = M × U × V
Work done = 42 × 11.5 × 3.33
Work done = 1608.39 J
Answer:
The correct answer would be A
Answer:
The correct option is;
a) Mike, he is within his target heart rate zone
Explanation:
The Target Heart Rate Zone (THRZ) is the range of the percentage of a person's maximal heart beat rate (MHR) targeted to be achieved during exercising. It is a very good way to gauge the comparative intensity of a person's exercise
Whereby, Joe's heart beat rate is below his THRZ and Mikes heart beat rate is within his THRZ, Mike is working harder.
Hence the correct option is (a) Mike, he is within his target heart rate zone.
