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3 years ago

According to the concept of punctuated equilibrium, _____.

1 answer:

7 0

<span>According to the concept of punctuated equilibrium, </span>new species evolve suddenly over relatively short periods of time (a few hundred to a thousand years), followed by longer periods in which little genetic change occurs. Hope this helps. Have a nice day.

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On the moon what would be the force of gravity acting on an object that has a mass of 7 kg?

Rudiy27

Answer:

Explanation:

4 0

3 years ago

The type of function that describes the amplitude of damped oscillatory motion is _______. The type of function that describes t

Salsk061 [2.6K]

Answer:

exponential

Explanation:

type of function that describes the amplitude of damped oscillatory motion is exponential because as we know that here function is

y = A × $e^{\frac{-bt}{2m}}$ × cos(ωt + ∅ ) ..................................... ( 1 )

here function A × $e^{\frac{-bt}{2m}}$ is amplitude

as per equation ( 1 )it is exponential

so that we can say that amplitude of damped oscillatory motion is exponential

8 0

3 years ago

a 200 kg crate is pushed horizontally with a force of 700 N. If the coefficient of friction is 0.2 calculate the acceleration of

Crazy boy [7]

Answer:

$a=1.54\ m/s^2$

Explanation:

<u>Net Force</u>

The Second Newton's law states that an object acquires acceleration when an external unbalanced net force is applied to it.

That acceleration is proportional to the net force and inversely proportional to the mass of the object.

It can be expressed with the formula:

$\displaystyle a=\frac{F_n}{m}$

Where

Fn = Net force

m = mass

The m=200 kg crate is pushed horizontally with a force Fa=700 N. The friction force opposes motion and a horizontal net force appears causing the acceleration.

The forces on the vertical direction are in balance since the crate does not accelerate in that direction, thus the weight and the normal force are equal:

N = W = mg

The friction force can be calculated by using the coefficient of friction μ:

$F_r=\mu N$

Calculating the normal force:

N = 200 * 9.8 = 1,960 N

The friction force is:

$F_r=0.2*1,960$

$F_r=392\ N$

The horizontal net force is:

$F_n = F_a-F_r=700\ N - 392\ N$

$F_n = 308\ N$

Finally, the acceleration is computed:

$\displaystyle a=\frac{308}{200}$

$\boxed{a=1.54\ m/s^2}$

3 0

3 years ago

A slingshot can project a pebble at a speed as high as 38.0 m/s. (a) If air resistance can be ignored, how high (in m) would a p

kipiarov [429]

Answer:

73.67 m

Explanation:

If projected straight up, we can work in 1 dimension, and we can use the following kinematic equations:

$y(t) = y_0 + V_0 * t + \frac{1}{2} a t^2$

$V(t) = V_0 + a * t$ ,

Where $y_0$ its our initial height, $V_0$ our initial speed, a the acceleration and t the time that has passed.

For our problem, the initial height its 0 meters, our initial speed its 38.0 m/s, the acceleration its the gravitational one ( g = 9.8 m/s^2), and the time its uknown.

We can plug this values in our equations, to obtain:

$y(t) = 38 \frac{m}{s} * t - \frac{1}{2} g t^2$

$V(t) = 38 \frac{m}{s} - g * t$

note that the acceleration point downwards, hence the minus sign.

Now, in the highest point, velocity must be zero, so, we can grab our second equation, and write:

$0 m = 38 \frac{m}{s} - g * t$

and obtain:

$t = 38 \frac{m}{s} / g$

$t = 38 \frac{m}{s} / 9.8 \frac{m}{s^2}$

$t = 3.9 s$

Plugin this time on our first equation we find:

$y = 38 \frac{m}{s} * 3.9 s - \frac{1}{2} 9.8 \frac{m}{s^2} (3.9 s)^2$

$y=73.67 m$

6 0

3 years ago

How can you pull a rope with equal but opposite forces

Ivahew [28]

You want to do it all by yourself ? Nothing to it !

Take a piece of rope that's maybe 12 to 18 inches long. Take one end
of the rope in each hand, raise your hands up in front of you, and make
like you're trying to stretch the rope. You'll automatically make the forces
of your hands equal and opposite, so that the rope just stays there in front
of you and doesn't move.

8 0

3 years ago