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3 years ago

PLZ HELP ME i don’t get this

Physics

1 answer:

Scorpion4ik [409]3 years ago

4 0

Explanation:

(i) Height of tree, h = 4 m

Mass of Ninja, m = 30 kg

The gravitational potential energy on the top branch of the tree is given by :

$P=mgh$

g is acceleration due to gravity

$P=30\ kg\times 9.8\ m/s^2\times 4\ m\\\\P=1176\ J$

(ii) If he were at a height of 2 meters from the ground, its potential energy will be :

$P=mgh$

g is acceleration due to gravity

$P=30\ kg\times 9.8\ m/s^2\times 2\ m\\\\P=588\ J$

Therefore, this is the required explanation.

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A 3.00-kg box is sliding along a frictionless horizontal surface with a speed of 1.8 m/s when it encounters a spring. (a) Determ

aniked [119]

Answer:

a) k= 3594,7 N/m

b) v= 0.55 m/s

Explanation:

a)
As the surface is horizontal, the only change in energy will be the change in kinetic energy, as the box comes to an stop after compressing the spring.
As we know that the surface is frictionless also, this change in kinetic energy must be equal to the change in the elastic potential energy of the spring.
So we can write the following equality:

$\Delta K = \Delta U$

where $\Delta K = \frac{1}{2}*m*v^{2}$

and $\Delta U = \frac{1}{2} * k* \Delta x^{2}$

Simplifying and replacing by the values, we get:

$3.00 kg* (1.8 m/s)^{2} = k* (0.052 m) ^{2}$

Solving for k:

$k = \frac{3.00kg*(1.8m/s)^{2} }{(0.052m)^{2}} = 3594.7 N/m$

k = 3594.7 N/m

b)
For this part, we can just apply the same equality, replacing the value of k by the one we got, and solving for the initial speed v:

$v = \sqrt{\frac{k*\Delta x^{2}}{m} } = \sqrt{\frac{3594.7N/m*(0.016m)^{2} }{3.00kg}} = 0.55 m/s$

v = 0.55 m/s

6 0

3 years ago

Acoustics is the study of sound. In large rooms, such as theaters where large orchestras perform, cushioned seats and carpeted f

stiv31 [10]

Answer:

soundproofing or absorbing

Explanation:

Acoustics is the study of waves, vibrations and sound and its most common applications lie in the sound and noise control industries. Acoustic protection is the application of soft and porous material to protect individuals against undesirable sounds and noises.

cushioned seats and carpeted floors are used in soundproofing to block the unwanted noise and sound.

The Cheapest Ways To Soundproof A Room

1. Rugs:

Rugs make excellent vibration dampeners.

2. Weather Stripping:

If you know that sound is getting into your room via the door or the windows then a very cheap and effective solution can be to use weather stripping.

3. Blankets.

4. Curtains.

5. Egg Cartons.

Homemade Soundproofing Panels

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3 years ago

5 What is the maximum speed at which a car round a curve of 25m radius on a level road if the coefficient of static friction bet

pshichka [43]

Hi there!

On a level road:

∑F = Ff (Force due to friction)

The net force is the centripetal force, so: