All categories

3 years ago

(12)

Physics

1 answer:

noname [10]3 years ago

4 0

Answer:

Power is the rate at which work is done or energy is transferred in a unit of time. Power is increased if work is done faster or energy is transferred in less time.

You might be interested in

What kind of air mass comes from the Gulf of Mexico? A. continental tropical B. continental polar C. maritime tropical D. mariti

Yakvenalex [24]

A. Hope this helps! (:

8 0

3 years ago

Read 2 more answers

If a 54 kg sprinter can accelerate from a standing start to a speed of 10 m/s in 3 s, what average power is generated?

lora16 [44]

Answer:

Power, P = 600 watts

Explanation:

It is given that,

Mass of sprinter, m = 54 kg

Speed, v = 10 m/s

Time taken, t = 3 s

We need to find the average power generated. The work done divided by time taken is called power generated by the sprinter i.e.

$P=\dfrac{W}{t}$

Work done is equal to the change in kinetic energy of the sprinter.

$P=\dfrac{\dfrac{1}{2}mv^2}{t}$

$P=\dfrac{\dfrac{1}{2}\times 54\ kg\times (10\ m/s)^2}{3\ s}$

P = 900 watts

So, the average power generated by the sprinter is 900 watts. Hence, this is the required solution.

3 0

3 years ago

Leoni is participating in four drawing competitions. If the probability of her losing any

Alex17521 [72]

Answer:

(a) $Probability = 0.7599$

(b) $Probability = 0.2646$

Explanation:

Represent losing with L and winning with W.

So:

$L = 0.7$ --- Given

$n = 4$

Probability of winning would be:

$W = 1 - L$

$W = 1 - 0.7$

$W = 0.3$

The question illustrates binomial probability and will be solved using the following binomial expansion;

$(L + W)^4 = L^4 + 4L^3W + 6L^2W^2 + 4LW^3 + W^4$

So:

Solving (a): Winning at least 1

We look at the above and we list out the terms where the powers of W is at least 1; i.e., 1,2,3 and 4

So, we have:

$Probability = 4L^3W + 6L^2W^2 + 4LW^3 + W^4$

Substitute value for W and L

$Probability = 4 * 0.7^3*0.3 + 6*0.7^2*0.3^2 + 4*0.7*0.3^3 + 0.3^4$

$Probability = 0.7599$

<em>Hence, the probability of her winning at least one is 0.7599</em>

Solving (a): Wining exactly 2

We look at the above and we list out the terms where the powers of W is exactly 2

So, we have:

$Probability = 6L^2W^2$

Substitute value for W and L

$Probability = 6*0.7^2*0.3^2$

$Probability = 0.2646$

<em>Hence, the probability of her winning exactly two is 0.2646</em>

6 0

2 years ago

Identify the particle that is NOT a subatomic particle.

Lyrx [107]

The answer is c, positron.

5 0

2 years ago

If you lie on the ground at night with no cover, you get cold rather quickly. Much of this is due to energy loss by radiation. A

marin [14]

Answer:

301.48 J/s

Explanation:

We are given;

Temperature of the sky dropping to −40∘C: T_o = -40°C = -40 + 273 = 233 K

Temperature of your skin and clothes: T = 30°C = 30 + 273 = 303 K

Body surface area of human body is around 2 m². But here only half of the body is facing the sky, Thus Area is: A = 2/2 = 1 m²

To solve this, we will use the equation for thermal heat transfer known as the Stefan bolt Mann equation.

ΔQ/Δt = εσA(T⁴ - (T_o)⁴)

Where;

ΔQ/Δt is the rate at which you body loses energy by radiation

ε is the emissivity of the human body with a value of 0.97

σ is Stefan boltzmann constant with a value of 5.67 X 10^(-8) W/m².K⁴

Thus;

ΔQ/Δt = 0.97 × 5.67 X 10^(-8) × 1(303⁴ - 233⁴)

ΔQ/Δt = 301.48 J/s

7 0

3 years ago