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Vlad [161]
3 years ago
5

Two objects are maintained at constant temperatures, one hot and one cold. Two identical bars can be attached end to end, as in

part a of the drawing, or one on top of the other, as in part b. When either of these arrangements is placed between the hot and the cold objects for the same amount of time, heat Q flows from left to right. Find the ratio Qa/Qb.
Physics
1 answer:
irina1246 [14]3 years ago
7 0

Answer:

Qa/Qb = k/2×2k = 1/4

Explanation:

a situation is series and b situation is parallel.

let conductance of each plate = k

so net conductance in series = k/2

net conductance in parallel = 2k

so Qa/Qb = k/2×2k = 1/4

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A cart of mass m = 0.12 kg moves with a speed v = 0.45 m/s on a frictionless air track and collides with an identical cart that
lina2011 [118]

Answer:

0.006075Joules

Explanation:

The final kinetic energy of the system is expressed as;

KE = 1/2(m1+m2)v²

m1 and m2 are the masses of the two bodies

v is the final velocity of the bodies after collision

get the final velocity using the law of conservation of momentum

m1u1 + m2u2 = (m1+m2)v

0.12(0.45) + 0/12(0) = (0.12+0.12)v

0.054 = 0.24v

v = 0.054/0.24

v = 0.225m/s

Get the final kinetic energy;

KE = 1/2(m1+m2)v

KE = 1/2(0.12+0.12)(0.225)²

KE = 1/2(0.24)(0.050625)

KE = 0.12*0.050625

KE = 0.006075Joules

Hence the final kinetic energy of the system is 0.006075Joules

5 0
2 years ago
With regard to pneumatic mechanical devices which afford protection against the formation of ice, which of the following stateme
Andreyy89

Answer:

the answer is The pneumatic mechanical device can only be used as a de-icing device.

Explanation:

An ice protection system prevents the formation of ice, or enables the aircraft to shed the ice before it can grow to a dangerous thickness. Ice protection systems are designed to keep atmospheric ice from accumulating on aircraft surfaces such as wings, propellers and engine intakes.

The pneumatic mechanical device is the Pneumatic deicing boots which was invented by the Goodrich Corporation in 1923. The pneumatic boot is usually made of layers of rubber, with one or more air chambers between the layers.

Any design which utilizes either a mechanical means of breaking the bond of ice to the surface, or which operates on a periodic cycle, is necessarily a de-ice system.

4 0
3 years ago
A tennis player strikes a tennis ball from underneath with her racket. The ball is sent straight up with an initial velocity of
Stels [109]
So the acceleration of gravity is 9.8 m/s so that’s how quickly it will accelerate downwards. You can use a kinematic equation to determine your answer. We know that initial velocity was 19 m/s, final velocity must be 0 m/s because it’s at the very top, and the acceleration is -9.8 m/s. You can then use this equation:

Vf^2=Vo^2+2ax

Plugging in values:

361=19.6x

X=18 m
6 0
2 years ago
"A boat that can travel at 4.0 km/h in still water crosses a river with a current of 2.0 km/h. At what angle must the boat be po
IRISSAK [1]

Answer:

30 degrees

Explanation:

8 0
2 years ago
1.Which statement is true when two objects are 20 miles apart but one is much bigger?
Paha777 [63]

1. C.  Gravitational attraction exists between the two objects.

Explanation:

Gravitational attraction is always exerted between two objects which have mass, and its magnitude is given by:

F=G\frac{m_1 m_2}{r^2}

where G is the gravitational constant, m1 and m2 the masses of the two objects, and r the separation between them. Since the two objects have for sure non-zero masses m1 and m2, even if they are 20 miles apart, the value of the gravitational attraction F is non-zero, so the correct answer is C.


2. D.  Two atoms come together to form a molecule.

Explanation:

this outcome is actually caused by the electrostatic forces between the two atoms, not by gravitational force. In fact, gravitational force becomes relevant only when the masses of the two objects involved are large enough: this is the case for planets, stars, galaxies, and objects in the universe. However, two atoms have very small masses, so the gravitational force between them is really negligible. On this smaller scales, the electrostatic force is much stronger than the gravitational force, so the electrostatic force is the real responsible for the formation of bonds between atoms.

7 0
3 years ago
Read 2 more answers
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