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3 years ago

Erica throws a tennis ball against a wall, and it bounces back. Which force is responsible for sending the ball back to Erica?

Physics

1 answer:

Anna71 [15]3 years ago

8 0

OPTIONS :

A.) the force that the ball exerts on the wall

B.) the frictional force between the wall and the ball

C.) the acceleration of the ball as it approaches the wall

D.) the normal force that the wall exerts on the ball

Answer: D.) the normal force that the wall exerts on the ball

Explanation: The normal force acting on an object can be explained as a force experienced by an object when it comes in contact with a flat surface. The normal force acts perpendicular to the surface of contact.

In the scenario described above, Erica's tennis ball experiences an opposite reaction after hitting the wall.This is in relation to Newton's 3rd law of motion, which states that, For every action, there is an equal and opposite reaction.

The reaction force in this case is the normal force exerted on the ball by the wall perpendicular to the surface of contact.

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A nuclear power plant generates 3000 MW of heat energy from nuclear reactions in the reactor's core. This energy is used to boil

kondaur [170]

Answer:

a) $\eta_{th} = 46.1\,\%$ , b) $\eta_{th,real} = 36.667\,\%$

Explanation:

a) The maximum possible thermal efficiency of the power plant is given by the Carnot's Cycle thermal efficiency, which consider a reversible power cycle according to the Second Law of Thermodynamics, whose formula is:

$\eta_{th} = \left(1-\frac{T_{L}}{T_{H}} \right)\times 100\,\%$

Where:

$T_{L}$ - Temperature of the cold reservoir (Condenser), measured in K.

$T_{H}$ - Temperature of the hot reservoir (Evaporator), measured in K.

The maximum possible thermal efficiency is:

$\eta_{th} = \left(1-\frac{298.15\,K}{553.15\,K} \right)\times 100\,\%$

$\eta_{th} = 46.1\,\%$

b) The actual efficiency of the plant is the ratio of net power to input heat rate expressed in percentage:

$\eta_{th, real} = \frac{\dot W}{\dot Q_{in}} \times 100\,\%$

$\eta_{th, real} = \frac{1100\,MW}{3000\,MW}\times 100\,\%$

$\eta_{th,real} = 36.667\,\%$

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3 years ago

Which of the

djyliett [7]

Answer:

Short THICC wire

Explanation:

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2 years ago

A lightbulb has an efficiency of 13.1%.How much light energy (not heat energy) is generated by the bulb every second if the bulb

maw [93]

Answer:

1.048 W

Explanation: Given that a lightbulb has an efficiency of 13.1%.How much light energy (not heat energy) is generated by the bulb every second if the bulb has a power pf 8W?

The input power = 8W

The output power = ?

The efficiency = 13.1%

Using the formula below:

Efficiency = (power output / power input) × 100

13.1 = (Power output / 8 ) × 100

0.131 = power output / 8

Cross multiply to make the power output the subject of formula

Power output = 0.131 × 8

Power output = 1.048 W

Therefore, the light energy (not heat energy) generated by the bulb every second is 1.048 W

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3 years ago

Anna applies a force of 19.5 newtons to push a book placed on a table. If the normal force of the book is 51.7 newtons, what is

GarryVolchara [31]

that would be given by

[email protected]

@ representing coefficient of kinetic friction.

thus 19.5/51.7 = 0.377

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3 years ago

Which of these questions are unit rates?

olga_2 [115]

B because it is basically 12 km/ hour

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3 years ago