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2 years ago

Coal is an example of kinetic or potential energy

Physics

2 answers:

alexdok [17]2 years ago

7 0

Potential energy is the correct answer

pav-90 [236]2 years ago

4 0

Answer:

Potential energy

Explanation:

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A rock is suspended from a string, and it accelerates downward. Which one of the following statements is correct? Group of answe

Tems11 [23]

Answer:

a. The magnitude of the tension in the string is greater than the magnitude of the weight of the rock.

Explanation:

During the motion of the rock while it is in downward motion we can say

$T - mg cos\theta = ma_c$

since it is performing circular motion so we will have its acceleration towards its center

$T = mgcos\theta + ma_c$

$a_c = \frac{v^2}{L}$

$T = mgcos\theta + \frac{mv^2}{L}$

So at the lowest point of the path we can say

$T = mg + \frac{mv^2}{L}$

so correct answer is

a. The magnitude of the tension in the string is greater than the magnitude of the weight of the rock.

4 0

2 years ago

Which receptors are responsible for the production of saliva (A) auditory receptors (B) optic receptors (C) skin receptors (D) t

Fudgin [204]

Answer:

$\large \boxed{\sf D. \ taste \ receptors}$

Explanation:

When activated, the receptor most likely prompting the production of saliva is the taste receptor. When food enters the mouth, the salivary glands produce the saliva upon the sensation of taste.

8 0

2 years ago

A concrete piling of 50 kg is suspended from a steel wire of diameter 1.0 mm and length 11.2 m. How much will the wire stretch?

pentagon [3]

Explanation:

It is given that,

Mass of concrete pilling, m = 50 kg

Diameter of wire, d = 1 mm

Radius of wire, r = 0.0005 m

Length of wire, L = 11.2

Young modulus of steel, $Y=20\times 10^{10}\ N/m^2$

The young modulus of a wire is given by :

$Y=\dfrac{\dfrac{F}{A}}{\dfrac{\Delta L}{L}}$

$Y=\dfrac{F.L}{A\Delta L}$

$\Delta L=\dfrac{F.L}{A.Y}$

$\Delta L=\dfrac{50\ kg\times 9.8\ m/s^2\times 11.2\ m}{\pi (0.0005\ m)^2\times 20\times 10^{10}\ N/m^2}$

$\Delta L=0.034\ m$

So, the wire will stretch 0.034 meters. Hence, this is the required solution.

8 0

3 years ago

A 2 kg object traveling at 5 m s on a frictionless horizontal surface collides head-on with and sticks to a 3 kg object initiall

Svetlanka [38]

Answer: (d)

Explanation:

Given

Mass of object $m=2\ kg$

Speed of object $u=5\ m/s$

Mass of object at rest $M=3\ kg$

Suppose after collision, speed is v

conserving momentum

$\Rightarrow mu+0=(m+M)v\\\\\Rightarrow v=\dfrac{2\times 5}{2+3}\\\\\Rightarrow v=2\ m/s$

Initial kinetic energy

$k_1=\dfrac{1}{2}\times 2\times 5^2\\\\k_1=25\ J$

Final kinetic energy

$k_2=\dfrac{1}{2}\times (2+3)\times 2^2\\\\k_2=10\ J$

So, it is clear there is decrease in kinetic energy . Thus, energy decreases and velocity becomes 2 m/s.

4 0

2 years ago

A Carnot engine operates between reservoirs at 600 and 300 K. If the engine absorbs 100 J per cycle at the hot reservoir, what i

PIT_PIT [208]

Answer:

W =50 J

Explanation:

given data:

T_h=600 k

T_L=300 k

Q_h=100 J

required:

<u>solution:</u>

║W║=║Q_h║(1-T_L/T_h)

=50 J

7 0

2 years ago

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