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3 years ago

Please Help!!!!

2 answers:

8 0

C. Chemical Energy is transformed to light energy and heat energy. The heat energy is keeping you warm and light energy is giving you the light you need to be able to read the book.

lapo4ka [179]3 years ago

7 0

Answer:

C. Chemical energy is transformed to light energy and heat energy.

Explanation:

Here it is given that the fire is used for two objectives

1) To warm yourself

which means we need some thermal energy so that we get the warmth from it.

2) To see to read the book

here in order read the book we required light of sufficient intensity so here we require light energy for this.

so from above requirements of energy we can say that here the energy contained in the wooden block is converted into the above forms

Also we know that energy contained in the wooden block is in the form of chemical energy so here correct answer will be

C. Chemical energy is transformed to light energy and heat energy.

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A student whirls a rubber stopper attached to a string in a horizontal circle above her head. If the radius of the stopper in ci

alexandr402 [8]

Answer:

$v = 12.57 m/s$

Explanation:

As we know that the radius of the circular motion is given as

$R = 50.00 cm$

time period of the motion is given as

$T = 0.2500 s$

now we know that it is moving with uniform speed

so it is given as

$v = \frac{2\pi R}{T}$

now plug in all data

$v = \frac{2\pi(0.50)}{0.25}$

$v = 12.57 m/s$

3 0

3 years ago

2. A rock is dropped off a bridge. How fast is the rock

zhenek [66]

Answer:

a) The velocity of rock at 1 second, v = 9.8 m/s

b) The velocity of rock at 3 second, v = 29.4 m/s

c) The velocity of rock at 5.5 second, v = 53.9 m/s

Explanation:

Given data,

The rock is dropped from a bridge.

The initial velocity of the rock, u = 0

a) The velocity of rock at 1 second,

Using the first equation of motion

v = u + gt

v = 0 + 9.8 x 1

v = 9.8 m/s

b) The velocity of rock at 3 second,

v = u + gt

v = 0 + 9.8 x 3

v = 29.4 m/s

c) The velocity of rock at 5.5 second,

v = u + gt

v = 0 + 9.8 x 5.5

v = 53.9 m/s

5 0

3 years ago

A 4.25 kg block is sent up a ramp inclined at an angle theta=37.5° from the horizontal. It is given an initial velocity ????0=15

wel

Answer:

d = 11.79 m

Explanation:

Known data

m=4.25 kg : mass of the block

θ =37.5° :angle θ of the ramp with respect to the horizontal direction

μk= 0.460 : coefficient of kinetic friction

g = 9.8 m/s² : acceleration due to gravity

Newton's second law:

∑F = m*a Formula (1)

∑F : algebraic sum of the forces in Newton (N)

m : mass s (kg)

a : acceleration (m/s²)

We define the x-axis in the direction parallel to the movement of the block on the ramp and the y-axis in the direction perpendicular to it.

Forces acting on the block

W: Weight of the block : In vertical direction

N : Normal force : perpendicular to the ramp

f : Friction force: parallel to the ramp

Calculated of the W

W= m*g

W= 4.25 kg* 9.8 m/s² = 41.65 N

x-y weight components

Wx= Wsin θ= 41.65*sin 37.5° = 25.35 N

Wy= Wcos θ =41.65*cos 37.5° =33.04 N

Calculated of the N

We apply the formula (1)

∑Fy = m*ay ay = 0

N - Wy = 0

N = Wy

N = 33.04 N

Calculated of the f

f = μk* N= 0.460*33.04

f = 15.2 N

We apply the formula (1) to calculated acceleration of the block:

∑Fx = m*ax , ax= a : acceleration of the block

-Wx-f = m*a

-25.35-15.2 = (4.25)*a

-40.55 = (4.25)*a

a = (-40.55)/ (4.25)

a = -9.54 m/s²

Kinematics of the block

Because the block moves with uniformly accelerated movement we apply the following formula to calculate the final speed of the block :

vf²=v₀²+2*a*d Formula (2)

Where:

d:displacement (m)

v₀: initial speed (m/s)

vf: final speed (m/s)

Data:

v₀ = 15 m/s

vf = 0

a = -9.54 m/s²

We replace data in the formula (2) to calculate the distance along the ramp the block reaches before stopping (d)

vf²=v₀²+2*a*d

0 = (15)²+2*(-9.54)*d

2*(9.54)*d = (15)²

(19.08)*d = 225

d = 225 / (19.08)

d = 11.79 m

3 0

3 years ago

The number of outer shell electrons determines the chemical properties of an element?

Ivan

Yes, it is true to a certain that the number of outer shell electrons determines the chemical properties of an element, only because this determines how the element interacts with other elements.

3 0

3 years ago

Once a disk forms around a star, the process of planetary formation can begin. Rank the evolutionary stages for the formation of

PolarNik [594]

Answer: See explanation

Explanation:

The evolutionary stages for the formation of planets from earliest to latest will be:

1. Dust keeps matter inside the disk cool enough for planet formation to start

2. Dust grains form condensation nuclei on which surrounding atoms condense to form small clumps of matter.

3. Small clumps of matter stick together via the process of accretion to form planetesimals a few hundred kilometers in diameter.

4. Planetesimals begin to accrete, forming protoplanets.

5. A collection of a few planet-sized protoplanets remain in a fairly cleared out disk around the star

6 0

3 years ago