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3 years ago

7

HELP!!! When fat comes in contact with sodium hydroxide, it produces soap and glycerin. Determine whether this is a physical cha

nge or a chemical change. Explain your answer.

1 answer:

dimaraw [331]3 years ago

5 0

Answer:it's a chemical change.physical changes occur without 2 or more reactants,a reaction,and a product

Explanation:

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A horizontal spring attached to a wall has a force constant of k = 860 N/m. A block of mass m = 1.60 kg is attached to the sprin

trasher [3.6K]

(a) 1.08 J

The elastic potential energy stored in the block at any position x is given by

$U=\frac{1}{2}kx^2$

where

k is the spring constant

x is the displacement relative to the equilibrium position

Here we have

k = 860 N/m

x = 5.00 cm = 0.05 m is the position of the block

Substituting, we find

$U=\frac{1}{2}(860 N/m)(0.05 m)^2=1.08 J$

(b) 1.16 m/s

The total mechanical energy of the spring-mass system is equal to the potential energy found at point (a), because there the system was at its maximum displacement, where the kinetic energy (because the speed is zero).

At the equilibrium position, the mechanical energy is sum of kinetic and potential energy

E = K + U

However, at equilibrium position x = 0, so U = 0. Therefore, the kinetic energy is equal to the total energy found at point (a)

$E=K= \frac{1}{2}mv^2 = 1.08 J$

where

m = 1.60 kg is the mass of the block

v is the speed

Solving for v, we find

$v=\sqrt{\frac{2K}{m}}=\sqrt{\frac{2(1.08 J)}{1.60 kg}}=1.16 m/s$

(c) 1.00 m/s

When the block is at position x = 2.50 cm, the mechanical energy is sum of kinetic and potential energy:

$E=K+U=\frac{1}{2}mv^2 + \frac{1}{2}kx^2$

where

E = 1.08 J is the total mechanical energy

m = 1.60 kg is the mass

v is the speed

k = 860 N/m

x = 2.50 cm = 0.025 m is the displacement

Solving for v, we find

$v = \sqrt{\frac{2E - kx^2}{m}}=\sqrt{\frac{2(1.08 J)-(860 N/m)(0.025 m)^2}{1.60 kg}}=1.00 m/s$

8 0

3 years ago

A group of physics students hypothesize that for an experiment they are performing, the speed of an object sliding down an incli

goblinko [34]

Answer:

v = 2.974

Explanation:

Perhaps the formula should be

v = √(2*g*d (sin(θ) - uk*cos(θ) ) This is a bit easier to read.

v = √(2* 9.80*0.725(0.707 - 0.12*0.707) ) Substitute values. Find 2*g*d

v = √14.21 * (0.707 - 0.0849) Figure out Sin(θ) - uk cos(θ)

v = √14.21 * (0.6222)

v = √8.8422 Take the square root of the value

v = 2.974

6 0

3 years ago

Read 2 more answers

Earths energy sources include renewable and non renewableresources. name at least three sources of energy that could be used in

enot [183]

Electricity.

Solar Energy

Wind Energy

In a home, the best option as a source of energy is electricity. Though some choose to use solar energy to power their devices, electricity is more cost effective.

6 0

3 years ago

Physics help please

zhuklara [117]

Answer: 37.981 m/s

Explanation:

This situation is related to projectile motion or parabolic motion, in which the travel of the ball has two components: <u>x-component</u> and <u>y-component.</u> Being their main equations as follows:

<u>x-component: </u>

$x=V_{o}cos\theta t$ (1)

Where:

$x=52 m$ is the point where the ball strikes ground horizontally

$V_{o}$ is the ball's initial speed

$\theta=0$ because we are told the ball is thrown horizontally

$t$ is the time since the ball is thrown until it hits the ground

<u>y-component: </u>

$y=y_{o}+V_{o}sin\theta t+\frac{gt^{2}}{2}$ (2)

Where:

$y_{o}=120m$ is the initial height of the ball

$y=0$ is the final height of the ball (when it finally hits the ground)

$g=-9.8m/s^{2}$ is the acceleration due gravity

Knowing this, let's start by finding $t$ from (2):

<u></u>

$0=y_{o}+V_{o}sin(0\°) t+\frac{gt^{2}}{2}$ (3)

$0=y_{o}+\frac{gt^{2}}{2}$

$t=\sqrt{\frac{-2 y_{o}}{g}}$ (4)

$t=\sqrt{\frac{-2 (120 m)}{-9.8m/s^{2}}}$ (5)

$t=4.948 s$ (6)

Then, we have to substitute (6) in (1):

$x=V_{o}cos(0\°) t$ (7)

And find $V_{o}$ :

$V_{o}=\frac{x}{t}$ (8)

$V_{o}=\frac{52 m}{4.948 s}$ (9)

$V_{o}=10.509 m/s$ (10)

On the other hand, since we are dealing with constant acceleration (due gravity) we can use the following equation to find the value of the ball's final velocity $V$ :

$V=V_{o} + gt$ (11)

$V=10.509 m/s + (-9.8 m/s^{2})(4.948 s)$ (12)

$V=-37.981 m/s$ (13) This is the ball's final velocity, and the negative sign indicates its direction is downwards.

However, we were asked to find the <u>ball's final speed</u>, which is the module of the ball's final vleocity vector. This module is always positive, hence the speed of the ball just before it strikes the ground is 37.981 m/s (positive).

5 0

3 years ago

Explain what the core muscles do and why it's important to have a strong set of core muscles.

Alika [10]

Answer:

Since your spine runs by your core, having a strong core will help protect and stabilize your spine, and you're also are able to control movements such as walking or standing better with a strong core.

7 0

3 years ago