An ant walks 2 m in a straight line over a period of 40 s. What is the average speed of the ant?

The force generated by a long muscle varies as it contracts through its range of movement. At which point is the greatest force

Sedaia [141]

Answer:

When the muscle is completely contract.

Explanation:

Remember the that maximum force of a muscle is when is completely contract. A characteristic of a muscle is that can contract and can relax in the opposite direction. In this way, when all the microfibers of the muscle are join together (they are contract) is when the maximum tissue force is applied.

With exercise the fibers of the muscles can grow or reproduce to strength the muscle.

8 0

4 years ago

You charge an initially uncharged 65.7-mf capacitor through a 39.1-Ï resistor by means of a 9.00-v battery having negligible int

uysha [10]

In a RC-circuit, with the capacitor initially uncharged, when we connect the battery to the circuit the charge on the capacitor starts to increase following the law:
$Q(t) = Q_0 (1-e^{-t/\tau})$
where t is the time, $Q_0 = CV$ is the maximum charge on the capacitor at voltage V, and $\tau = RC$ is the time constant of the circuit.
Using this law, we can answer all the three questions of the problem.

1) Using $R=39.1 \Omega$ and $C= 65.7 mF=65.7\cdot 10^{-3}F$ , the time constant of the circuit is:
$\tau = RC=(39.1 \Omega)(65.7 \cdot 10^{-3}F)=2.57 s$

2) To find the charge on the capacitor at time $t=1.95 \tau$ , we must find before the maximum charge on the capacitor, which is
$Q_0 = CV=(65.7 \cdot 10^{-3}F)(9 V)=0.59 C$
And then, the charge at time $t=1.95 \tau$ is equal to
$Q(1.95 \tau) = Q_0 (1-e^{-t/\tau})=(0.59 C)(1-e^{-1.95})=0.51 C$

3) After a long time (let's say much larger than the time constant of the circuit), the capacitor will be fully charged, this means its charge will be $Q_0 = 0.59 C$ . We can see this also from the previous formule, by using $t=\infty$ :
$Q(t) = Q_0 (1-e^{-\infty})=Q_0(1-0) = 0.59 C$

4 0

3 years ago

Explain why filing cabinets are<br>designed so that only one draw<br>can be pulled out at a time.

natta225 [31]

Answer:

Cabinets are made to open one at a time so that there's not much of space taken up when all the drawers are open. Hope this helps.

7 0

3 years ago

A boy throws a stone straight upward with an initial speed of 15m/s. What maximum height will the stone reach before falling bac

Vitek1552 [10]

$height=\frac{velocity^2}{2gravity}\\\\
velocity=15\frac{m}{s}\\\\
g=9,8\frac{m}{s^2}\\\\height=\frac{15^2}{2*9,8}=\frac{225}{19,6}\\\\
\boxed{height=11,48\ meters}$

6 0

3 years ago

A toy plane is flying in a horizontal circle by being attached to a 0.75 meter string. The plane has a mass of 101.7 grams and m

nadezda [96]

Answer:

F = 2,894 N

Explanation:

For this exercise let's use Newton's second law

F = m a

The acceleration is centripetal

a = v² / r

Angular and linear variables are related.

v = w r

Let's replace

F = m w² r

The radius r and the length of the rope is related

cos is = r / L

r = L cos tea

Let's replace

F = m w² L cos θ

Let's reduce the magnitudes to the SI system

m = 101.7 g (1 kg / 1000g) = 0.1017 kg

θ = 5 rev (2π rad / rev) = 31,416 rad

w = θ / t

w = 31.416 / 5.1

w = 6.16 rad / s

F = 0.1017 6.16² 0.75 cos θ

F = 2,894 cos θ

The maximum value of F is for θ equal to zero

F = 2,894 N

7 0

3 years ago