Explain why a wooden spoon a better choice then a metal spoon for stirring a boiling pot I soup

1 answer:

5 0

Metal is a conductor of heat while wood does the opposite so having a wooden spoon would keep you from burning your hand

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A 0.20 kg stone is dropped (from rest) from a height of 40.0 m above the ground. How far above the ground is the stone when it's

Jlenok [28]

The farthest is 12

And the ground has to be 30

7 0

3 years ago

Water at 288.7 k flows through a 15.24-cm. diameter horizontal pipe into a 190-l drum. determine the minimum time it will take t

nikdorinn [45]

The flow will be laminar if Reynold's number $N_{R}$ is less than 2000.

Use the Reynold's formula and rearrange to calculate velocity of water in the pipe.

$N_{R} = \frac{v D}{\nu}$

Where, $v$ is velocity of the fluid, $D$ is the diameter of pipe, and $\nu$ is the kinematic viscosity i.e. $1.12 \times 10^{-6} m^2/s$ for water at 288.7 K from Appendix.

So, velocity is:

$v = \frac{N_{R} \nu}{D}$

The flow rate <em>Q</em>:

$Q = vA=v\pi D^2/4=\frac{\frac{N_R \nu}{D} \pi D^2}{4} =[tex] t = \frac{V}{\frac{N_R \nu \pi D}{4}} = \frac{4V}{N_R \nu \pi D} =\frac{4 \times 190 L\frac{10^{-3} m^3}{L}}{2000 \times 1.12\times 10^{-6} m^2/s \pi 15.24 cm\frac{1 m}{100 cm}} = 2226.3 s \frac{1 min}{60 s}= 37.1 min$ [/tex]

Where A is the area of cross section of pipe.

The time taken to fill is:

$t = Q/V$

Where V is the capacity of the tank.

7 0

3 years ago

A 78.5-kg man is standing on a frictionless ice surface when he throws a 2.40-kg book horizontally at a speed of 11.3 m/s. With

kirill [66]

Answer:

The man moves across the ice with a speed of 0.345m/s.

Explanation:

From the conservation of linear momentum, we have that the total linear momentum before the book throw is equal to the total linear momentum just after it. Since the initial velocity of the system is zero (so the initial momentum is zero), we have that:

$m_mv_m+m_bv_b=0\\\\v_m=-\frac{m_b}{m_m} v_b$

Where $m_m$ is the mass of the man, $m_b$ is the mass of the book, and $v_m$ and $v_b$ are their velocities. Plugging in the given values, we can compute the speed of the man (ignoring the negative sign, because we care about the magnitude, not the direction):