Based on their composition materials can be divided into pure and

Which scientific term is defined as the rate at which work is accomplished?

Oliga [24]

Power is the scientific term defined as the rate at which work is accomplished. Power can be seen everywhere as it is applied to our everyday living. Power is seen when one pushes a heavy cart. It could be seen when a baseball hitter hits the ball.

7 0

3 years ago

An astronaut spends 3 months in space and then returns to Earth. When she returns to Earth, her muscles have weakened. This is b

Pepsi [2]

False. there's less gravitational force in space than on earth

6 0

3 years ago

Read 2 more answers

A man wishes to pull a crate 15m across a rough floor by exerting a force of 100 N. The

Darina [25.2K]

Answer:

option (E) is correct.

Explanation:

Work done is defined as the product of force and the distance in the direction of force.

force, f = 100 N

Coefficient of friction, = 0.25

distance = 15 m

So, net force F = f - friction force

F = 100 - 0.25 x m g

Work = (100 - 0.25 mg) x d cosθ

For minimum work, the angle should be maximum.

So, the value of θ is 76°.

thus, option (E) is correct.

3 0

3 years ago

Vitamins and iron are nutrients that provide energy to the human body.<br> A true<br> B false

SIZIF [17.4K]

I think it is A. but then you can also produce your own energy

4 0

2 years ago

In which medium does light travel faster: one with a critical angle of 27.0° or one with a critical angle of 32.0°? Explain. (Fo

Eddi Din [679]

Answer:

Among those two medium, light would travel faster in the one with a reflection angle of $32^{\circ}$ (when light enters from the air.)

Explanation:

Let $v_{1}$ denote the speed of light in the first medium. Let $v_{\text{air}}$ denote the speed of light in the air. Assume that the light entered the boundary at an angle of $\theta_{1}$ to the normal and exited with an angle of $\theta_{\text{air}}$ . By Snell's Law, the sine of $\theta_{1}\!$ and $\theta_{\text{air}}\!$ would be proportional to the speed of light in the corresponding medium. In other words:

$\displaystyle \frac{v_{1}}{v_{\text{air}}} = \frac{\sin(\theta_{1})}{\sin(\theta_{\text{air}})}$ .

When light enters a boundary at the critical angle $\theta_{c}$ , total internal reflection would happen. It would appear as if the angle of refraction is now $90^{\circ}$ . (in this case, $\theta_{\text{air}} = 90^{\circ}$ .)

Substitute this value into the Snell's Law equation:

$\begin{aligned}\frac{v_{1}}{v_{\text{air}}} &= \frac{\sin(\theta_{1})}{\sin(\theta_{\text{air}})} \\ &= \frac{\sin(\theta_{c})}{\sin(90^{\circ})} \\ &= \sin(\theta_{c})\end{aligned}$ .

Rearrange to obtain an expression for the speed of light in the first medium:

$v_{1} = v_{\text{air}} \cdot \sin(\theta_{1})$ .

The speed of light in a medium (with the speed of light slower than that in the air) would be proportional to the critical angle at the boundary between this medium and the air.

For $0 < \theta < 90^{\circ}$ , $\sin(\theta)$ is monotonically increasing with respect to $\theta$ . In other words, for $\!\theta$ in that range, the value of $\sin(\theta)\!$ increases as the value of $\theta\!$ increases.

Therefore, compared to the medium in this question with $\theta_{c} = 27^{\circ}$ , the medium with the larger critical angle $\theta_{c} = 32^{\circ}$ would have a larger $\sin(\theta_{c})$ . such that light would travel faster in that medium.

4 0

3 years ago