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3 years ago

Which of the following is a metal? Calcium (Ca) Iron (Fe) Sodium (Na) all of these

Physics

2 answers:

ANTONII [103]3 years ago

8 0

Iron (Fe) or at least it can be.

netineya [11]3 years ago

6 0

All of the above are metals

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An eagle is flying horizontally at a speed of 4.6 m/s when the fish in her talons wiggles loose and falls into the lake 4.2 m be

rewona [7]

Answer:

v = 9.07 m/s

the vertical component of the velocity of the fish relative to the water when it hits the water is 9.07 m/s

Explanation:

Given;

An eagle is flying horizontally at a speed of 4.6 m/s

Initial horizontal velocity uh = 4.6 m/s

Initial vertical velocity uy = 0

Height to fall d = 4.2 m

Acceleration due to gravity g = 9.8 m/s^2

The final vertical velocity of the fish when it hits the water can be calculated using the equation of motion;

v^2 = u^2 + 2as

v^2 = uy^2 + 2gd

uy = 0

v^2 = 2gd

v = √(2gd)

Substituting the given values;

v = √(2×9.8×4.2)

v = 9.073036977771 m/s

v = 9.07 m/s

the vertical component of the velocity of the fish relative to the water when it hits the water is 9.07 m/s

8 0

4 years ago

Which of the following would not be considered a projectile?

Naddika [18.5K]

Answer:

e. All of the above are projectile

Explanation:

A projectile is an object with motion, aka a non-zero speed. A cannonball throwing straight up, rolling down a slope, rolling off the edge of a tale, thrown through the air have motion. They all have speed and kinetic energy. Therefore they can all be considered a projectile.

5 0

3 years ago

What length of a certain metal wire of diameter 0.15 mm is needed for the wire to have a resistance of 15 ω? the resistivity of

Murljashka [212]

The resistance of the cylindrical wire is $R=\frac{\rho l}{A}$ .

Here $R$ is the resistance, $l$ is the length of the wire and $A$ is the area of cross section. Since the wire is cylindrical $A=\frac{\pi d^2}{4}$ . Rearranging the above equation,

$A=\frac{\rho l}{R}\\ \frac{\pi d^2}{4}=\frac{\rho l}{R}\\ l=\frac{\pi d^2 R}{4 \rho}$

Here $d=0.15, R=15, \rho=1.68(10^{-8})$ .

Substituting numerical values,

$l=\frac{\pi 0.15^2(10^{-6}) (15)}{4 (1.68)(10^{-8})} \\ l=15.78$

The length of the wire is $15.78 \;\;m$

5 0

4 years ago

When this pendulum swings, at which point is its kinetic energy the<br> highest? *

Eddi Din [679]

Answer:

The bottom/center of the pendulum

Explanation:

As it swings, the pendulum will have maximum potential energy at the top of its arc.

As it comes back towards the center that potential energy will convert into kinetic energy until it reaches the middle of its swing (when the pendulum is fully vertical) where all potential energy has been converted into kinetic energy.

This is when the kinetic energy is the highest

As it begins to move away from the center of its arc, that kinetic energy will convert into potential energy again, and the process repeats

5 0

3 years ago

Wagon wheel. While working on your latest novel about settlers crossing the Great Plains in a wagon train, you get into an argum

OverLord2011 [107]

Answer:

I = 16.7kgm²

Explanation:

Since, Torque is given by,

\tau = F*r = I*\alpha

here, I = Moment of inertia = ??

\alpha = angular acceleration of wheel = a/r

F = tangential tension acting on the wheel = T

a = acceleration of bag of sand = 2.95 m/s^2

r = radius of wheel = d/2 = 120/2 = 60 cm = 0.60 m

from force balance on sand bag,

mg - T = m*a

T = m*(g-a)

m = mass of sand bag = 20 kg

So, I = T*r/\alpha = m*(g-a)*r/(a/r)

Using known values:

I = 20*(9.81 - 2.95)*0.60/(2.95/0.60) = 16.74

I = 16.7 kgm² = Moment of inertia of wheel experimentally

also, Moment of inertia of wheel theoretically(I') = M*r²

given, M = mass of wheel = 70 kg

I' = 70*0.60²= 25.2 kgm² = Moment of inertia of wheel theoretically

7 0

3 years ago