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3 years ago

Feather is dropped from 13 m high after it has fallen 3 m what is its acceleration

Physics

1 answer:

iogann1982 [59]3 years ago

4 0

Answer:

Explanation:

The constant acceleration of any object, neglecting air resistance and friction, is always -9.8. Proof:

$s(t)=-4.9t^2+13$ which is the position of this feather before it is dropped. The first derivative of position is velocity, so the velocity function for the feather is:

$v(t)=-9.8t$ . We could find the velocity that the feather is experiencing at 3 seconds, but that is not what we are being asked. What we are being asked is the acceleration of the feather at 3 seconds. So we find the acceleration function of the feather:

a(t) = -9.8

It turns out that the time doesn't matter to acceleration due to gravity because feathers and elephants all fall under the same pull.

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A duck is 12 m from the edge of a pond. A student stands in the middle of the pond

olganol [36]

Answer:

The wavelength is 2 meters

Explanation:

The relationship between the frequency, the speed and the wavelength is given by the relation;

v = f × λ

The given parameters are;

The distance of the duck from the edge of the pond = 12 m

The number of ripples produced per second = Frequency, f = 2 Hz

The time it takes the ripple to reach the edge of the pond after travelling past the duck = 3 seconds

Therefore, speed of the wave, v = Distance/time = 12 m/(3 s) = 4 m/s

The wavelength, λ, is therefore;

λ = v/f = (4 m/s)/(2 Hz) = 2 meters.

6 0

3 years ago

Write the y-equation for a wave traveling in the negative x-direction with wavelength 50 cm, speed 4.0 m/s, and amplitude 5.0 cm

Zanzabum

Answer:

$y = A sin(2\pi(\dfrac{x}{50})+ 8 t)$

Explanation:

given,

wavelength, λ = 50 cm

speed, v = 4 m/s

Amplitude, A = 5 cm

general equation of the wave along x- axis

$y = A sin(2\pi(\dfrac{x}{\lambda})\pm \nu t)$

sign is positive when wave is traveling in negative direction

now,

$\nu = \dfrac{v}{\lambda}$

$\nu = \dfrac{4}{0.5}$

$\nu = 8\ s^{-1}$

inserting all the values

$y = A sin(2\pi(\dfrac{x}{50})+ 8 t)$

Hence, the y-equation of wave is equal to $y = A sin(2\pi(\dfrac{x}{50})+ 8 t)$

7 0

3 years ago

A cart moves with negligible friction or air resistance along a roller coaster track. The cart starts from rest at the top of a

lina2011 [118]

Answer:

hinit = 17.5 m

Explanation:

Assuming no friction present, the mechanical energy must be conserved, which means that at any point of the trajectory, the sum of the gravitational potential energy and the kinetic energy must keep the same.
At the top of the hill, since it starts from rest, all the energy must be potential, and we can express it as follows:

$E_{o} = U_{o} = m*g*h_{init} (1)$

When the car arrives to the top of the second hill, as we know that it is lower than the first one, the energy of the car, must be part gravitational potential energy, and part kinetic energy.
We can express this final energy as follows:

$E_{f} = U_{f} + K_{f} = m*g* h_{2} + \frac{1}{2} *m*v_{f} ^{2} (2)$

In order to find hinit, we need to make (1) equal to (2), and solve for it.
In (2) we have the value of h₂ (10 m), but we still need the value of the speed at the top of the second hill, vf.
Now, when the car is at the top of the hill, there are two forces acting on it, in opposite directions: the normal force (upward) and the weight (downward).
We know also that there is a force that keeps the car along the circular track, which is the centripetal force.
This force is just the net downward force acting on the car (it's vertical at the top), and is just the difference between the weight and the normal force.
If the cart just barely loses contact with the track at the top of the second hill, this means that at that point the normal force becomes zero.
So, the centripetal force must be equal to the weight.
The centripetal force can be expressed as follows:

$F_{c} = m*\frac{v_{f} ^{2}}{R} (3)$

We have just said that (3) must be equal to the weight:

$F_{c} = m*\frac{v_{f} ^{2}}{R} = m*g (4)$

Simplifying, and rearranging, we can solve for vf², as follows:

$v_{f}^{2} = R*g (5)$

Replacing (5) in (2), simplifying and rearranging in (1) and (2) we finally have:

$h_{init} = h_{2} + \frac{1}{2} R = 10m + 7.5 m = 17.5 m (6)$

7 0

3 years ago

Please help! I'll give brainliest.

Mamont248 [21]

Answer:

Below

Explanation:

Surface waves cannot pass through the Earth's mantle but travel along the Earth's crust. They are more destructive than body waves.

Have a good night ((:

7 0

3 years ago

An electron has a velocity of 1.50 km/s (in the positive x direction) and an acceleration of 2.00 ✕ 1012 m/s2 (in the positive z

olga nikolaevna [1]

Answer:

see explanation

Explanation:

Given that,

velocity of 1.50 km/s = 1.50 × 10³m/s

acceleration of 2.00 ✕ 1012 m/s2

electric field has a magnitude of strength of 18.0 N/C

$\bar F= q[\bar E + \bar V \times \bar B]\\\\\bar F = [\bar E + \bar V \times ( B_x \hat i +B_y \hat j +B_z \hat z )]\\\\\\m \bar a = [\bar E + \bar V \times ( B_x \hat i +B_y \hat j +B_z \hat z )]$

$9.1 \times 10^-^3^1 \times 2\times 10^1^2 \hat k=-1.6\times10^-^1^9 \hat k [18\hat k+ 1.5\times 10^3 \hat i \times (B_x \hat i +B_y \hat j +B_z \hat k)]$ $42.2 \times 10^-^1^9 \hat k = -2.4 \times 10^1^6B_y \hat k + 2.4 \times 10 ^1^6 \hat j B_z\\$

$B_x = undetermined$

$B_y = \frac{42.2 \times 10^-^1^9}{-2.4 \times 10^-^1^6} \\\\= - 0.0176 T$

$B_z = 0T$

8 0

4 years ago