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dybincka [34]
4 years ago
9

A girl on a bridge throws a rock

Physics
1 answer:
Anon25 [30]4 years ago
6 0

t = 1.3 s.

To solve this exercise we have to use the freefall equation t = (v-v₀)/g. v = 0 due the final velocity when the rock reach the ground is 0.

With v₀ = -12.5m/s and g = 9.8m/s²

t = -(-12.5m/s)/9.8m/s²

t = 1.3 s

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Compare the forces in a small nucleus to the forces in a large nucleus
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The comparison of the forces in a small nucleus to the forces of a large one is the fact that they are capable of holding the protons and neutrons which made it no matter what their size may be. Therefore, as long as there is a nucleus, their forces can both hold together the two atoms tight.
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A 2.2 kg model rocket is shot straight up in the air from the ground, with an initial velocity of 36.4 m/s. The rocket reaches i
alexandr1967 [171]

Answer:

Explanation:

Ignoring friction, the initial kinetic energy will convert to maximum potential energy at its highest point.

PE = KE

mgh = ½mv²

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    h = 67.53109...

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2 years ago
A vertical spring withk= 245N/m oscillates with an amplitude of 19.2cm when 0.457kg hangs from it. The mass posses through the e
Makovka662 [10]

Answer:

 y = -19.2 sin (23.15t) cm

Explanation:

The spring mass system is an oscillatory movement that is described by the equation

      y = yo cos (wt + φ)

Let's look for the terms of this equation the amplitude I

     y₀ = 19.2 cm

Angular velocity is

     w = √ (k / m)

     w = √ (245 / 0.457

     w = 23.15 rad / s

The φ phase is determined for the initial condition   t = 0 s ,  the velocity is negative v (0) = -vo

The speed of the equation is obtained by the derivative with respect to time

     v = dy / dt

     v = - y₀ w sin (wt + φ)

For t = 0

     -vo = -yo w sin φ

The angular and linear velocity are related v = w r

      v₀ = w r₀

      v₀ = v₀ sinφ

      sinφ = 1

      φ = sin⁻¹ 1

      φ = π / 4    rad

Let's build the equation

      y = 19.2 cos (23.15 t + π/ 4)

Let's use the trigonometric ratio π/ 4 = 90º

      Cos (a +90) = cos a cos90 - sin a sin sin 90 = 0 - sin a

       y = -19.2 sin (23.15t) cm

8 0
3 years ago
How much rope would need to be pulled through a pulley with a mechanical advantage of 2 to lift a load 4 ft?
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8 feet of rope is needed.
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