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3 years ago

Newton's second law of motion describes inertia. True False

Physics

2 answers:

ladessa [460]3 years ago

7 0

False. the first law describes inertia

hichkok12 [17]3 years ago

7 0

Answer:

yep it is false the definition says nothing about inertia

Explanation:

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How does a football work

nikdorinn [45]

Answer:

As the football travels up, gravity slows it down until it reaches a point where it stops briefly at its highest peak; then the football comes down, and gravity accelerates it until it hits the ground hard.

Have a great day!

8 0

3 years ago

A ray is incident on a film of thickness t and the index of refraction n=1.6 at an angle θ = 35 degrees. Find the angle of refra

lidiya [134]

Answer

Given,

refractive index of film, n = 1.6

refractive index of air, n' = 1

angle of incidence, i = 35°

angle of refraction, r = ?

Using Snell's law

n' sin i = n sin r

1 x sin 35° = 1.6 x sin r

r = 21°

Angle of refraction is equal to 21°.

Now,

distance at which refractive angle comes out

d = 2.5 mm

α be the angle with horizontal surface and incident ray.

α = 90°-21° = 69°

t be the thickness of the film.

So,

$tan \alpha = \dfrac{t}{d/2}$

$tan 61^0 = \dfrac{t}{2.5/2}$

t = 2.26 mm

Hence, the thickness of the film is equal to 2.26 mm.

4 0

3 years ago

An air conditioner runs 15 minutes each hour on a hot summer day. It is on a 240 volt circuit and uses 21 amps. Rate is $.10/kWh

Helen [10]

Answer:

Approximately $\$ 3.02$ .

Explanation:

Note that the electric rate in this question is in the unit dollar-per- ${\rm kWh}$ , where $1\; {\rm kWh}$ is the energy to run an appliance of power $1\; {\rm kW}$ for an hour.

Number of minutes for which the air conditioner is running in that day: $15 \times 24 = 360\; \text{minute}$ . Apply unit conversion and ensure that this time is measured in hours (same as the unit of the electric rate.)

$\begin{aligned} \text{time} &= 360\; \text{minute} \times \frac{1\; \text{hour}}{60\; \text{minute}} = 6\; \text{hour} \end{aligned}$ .

The power of this air conditioner is:

$\begin{aligned} \text{power} &= \text{voltage} \times \text{current} \\ &= 240\; {\rm V} \times 21\; {\rm A} \\ &= 5040\; {\rm W} \\ &= 5.04\; {\rm kW} \end{aligned}$ .

Thus, the energy that this air conditioner would consume would be:

$\begin{aligned}\text{energy} &= \text{power} \times \text{time} \\ &= 5.04\; {\rm kW} \times 6\; \text{hour} \\ &= 30.24\; {\rm kWh} \end{aligned}$ .