When children use the word “doggie” to refer to every four-legged animal they see, _________

What is a scientific theory? A law that is always true a hypothesis about nature and educated guess based on observations an exp

egoroff_w [7]

Answer:

an explanation on how the natural world works

Explanation:

A scientific theory is simply an explanation into how the natural world works. Scientific theory is formulated after a series of hypothesis that has ascertained how true an observation is.

A theory is provides explanation into an observed feature. It can be disproved when new evidences are found. This brings about revision into scientific proofs.

5 0

3 years ago

A high powered rifle can shoot a bullet at a speed of 1500 mi/hr.

kumpel [21]

Initial velocity of the billet is maximum, once out if the rifle it begins to slow down

7 0

3 years ago

1.60 kg frictionless block is attached to an ideal spring with force constant 315 N/m . Initially the spring is neither stretche

Tatiana [17]

Answer:

(a). The amplitude of the motion is 0.926 m.

(b). The block’s maximum acceleration is 182.31 m/s².

(c). The maximum force the spring exerts on the block is 291.69 N.

Explanation:

Given that,

Mass of block =1.60 kg

Force constant = 315 N/m

Speed = 13.0 m/s

(a). We need to calculate the amplitude of the motion

Using conservation of energy

$\dfrac{1}{2}mv^2=\dfrac{1}{2}kA^2$

$A^2=\dfrac{mv^2}{k}$

Put the value into the relation

$A^2=\dfrac{1.60\times13.0^2}{315}$

$A=\sqrt{0.858}$

$A=0.926\ m$

(b). We need to calculate the block’s maximum acceleration

Using formula of acceleration

$a=A\omega^2$

$a=A\times\dfrac{k}{m}$

Put the value into the formula

$a=0.926\times\dfrac{315}{1.60}$

$a=182.31\ m/s^2$

(c). We need to calculate the maximum force the spring exerts on the block

Using formula of force

$F=ma$

Put the value into the formula

$F= 1.60\times182.31$

$F=291.69\ N$

Hence, (a). The amplitude of the motion is 0.926 m.

(b). The block’s maximum acceleration is 182.31 m/s².

(c). The maximum force the spring exerts on the block is 291.69 N.

7 0

3 years ago

7 One lb of Refrigerant 134a contained within a piston–cylinder assembly undergoes a process from a state where the temperature

julsineya [31]

Answer:

$\Delta S = S_2-S_1 = 0.08835 \frac {BTU} {Lb ^ {\circ} R}$

Explanation:

A) In order to solve the table it is necessary to consult tables A11-E and A10E for refrigerant R134-a

In this way we obtain that:

$S_1 = S_f = 0.0648 \frac {BTU} {Lb. ^ {\circ} R}$

In this way,

$S_2 = S_f + x_2 (S_g-S_f) = 0.0902 + 0.5 (0.2161-0.0902)$

$S_2 = 0.15315 \frac {BTU} {Lb ^ {\circ} R}$

In this way the entropy change is,

$\Delta S = S_2-S_1 = 0.08835 \frac {BTU} {Lb. ^ {\°} R}$

B) Whenever entropy yields a positive result, the process can be carried out adiabatically.

7 0

3 years ago

A closed box is filled with dry ice at a temperature of -87.1°C, while the outside temperature is 17.6°C. The box is cubical, me

natta225 [31]

Answer:

K=24.17 x 10⁻² J s⁻¹c⁻¹m⁻¹

Explanation:

Rate of flow of heat through a material is given by the following expression

$\frac{Q}{t} =\frac{KA\delta T}{d}$

where Q is amount of heat flowing in time t through area A and a medium of thickness d having two faces at temperature difference δT . K is thermal conductivity of the medium .

Here Q = 3.34 x 10⁶/6 , t = 24 x 60 x 60 = 86400 s , A = .332 X .332 = .0110224 m² , δT = 104.7

Put these values here

$\frac{3.34\times10^6}{6\times86400}= \frac{k\times.011224\times104.7}{4.41\times10^{-2}}$

$K=\frac{3.34\times4.41\times10^4}{6\times86400\times.011224\times104.7}$

K=24.17 x 10⁻² J s⁻¹c⁻¹m⁻¹

4 0

3 years ago

When children use the word “doggie” to refer to every four-legged animal they see, __________ occurs.