A farmer uses 3450 J of energy on a wheel and axle to lift a 15 kg bucket of water 20 m to the top of her well. What is the efficiency of the system?

Answers

Answer 1

Answer:

Efficiency is the measure of how efficient a process is. It is used to assess the ability of a process in avoiding waste energy, materials, money and time in doing a desirable output. It is calculated as;

Efficiency = useful energy ouput / total energy input

Efficiency = 15(9.81)(20) / 3450 = 0.85

Answer 2

Answer:

Output= m*g*h = 15*9.8*20 = 2,940J

Input= 3450J (given)

Efficiency = output/input = 2,940/3450 = 0.85% efficient

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If a grocery cart with a mass of 16.5 kg accelerates at +2.31 m/s2 against a frictional force of -15.0 N, what is the applied force?

Answers

Call the applied force 'A'. (Clever ?)

The forces on the cart are 'A' forward and 15 N backward.

The net force on the art is (A-15) forward.

F = m a

Net forward force = (mass of the cart) x (its forward acceleration)

(A - 15) = (16.5) x (2.31)

A - 15 = 38.115

Add 15 to each side:

A = 53.115 newtons

2th Law of Newton:

$\vec{R}=m.a\n \n \vec{R}=\vec{F} -\vec{F_a}=m.a\n \n \vec{F}-15=16.5*2.31\n \n \vec{F}=38.115+15\n \n \boxed{\vec{F}=53.115 \ N}$

According to Levin, how can black holes be investigated?

Answers

By observing their effect on their surroundings.

A sled with rider having a combined mass of 110 kg travels over the perfectly smooth icy hill shown in the accompanying figure. How far does the sled land from the foot of the cliff?

Answers

The sled land is "25.531 m" far from the foot of the cliff.

According to the question,

The velocity of the top = $V_t$

then,

→ $0.5 \ Vt^2-0.5 \ Vi^2 = -mgh$

→ $0.5 \ Vt^2 = 0.5 \ Vi^2- 9.8* 11$

→ $0.5 \ Vt^2 = 0.5 \ Vi^2- 107.8$

→ $=17.04 \ m/sec$

Now,

The projectile motion in horizontal direction,

→ $S_y = 11 = ut-0.5 \ gt^2$

$= 0-0.5* 9.8 \ t^2$

or,

→ $S_x = 17.04* 1.498$

$= 25.53 \ m$

Thus the above answer is the correct one.

Learn more:

brainly.com/question/13027204

Find the speed the sled has at the top of the hill from the law of conservation of mechanical energy. Equate the kinetic energy at the bottom of the hill to the kinetic plus potential energy at the top :

0.5mv₀² = 0.5mv² + mgh
v = √[v₀² - 2gh]
= √[(22.5m/s)² - (2 x 9.80m/s² x 11.0m)]
= 17.0m/s

From the time independent kinematics equation, find the vertical component of the sleds final velocity (note that the vertical component of the sleds initial velocity is zero) :

v² = v₀² + 2gΔy
= 0 + 2(-9.80m/s²)(-11.0m)
= -14.7m/s (select the neg root, because motion is downward)

With this you can find the time vertically which is the same horizontally :

v = v₀ + gt
t = (v - v₀) / g
= (-14.7m/s - 0) / -9.80m/s²
= 1.50s

Now, the horizontal distance is :

Δx = (v₀ + v)t / 2
= (17.0m/s + 17.0m/s)1.50s / 2
= 25.5m

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A container filled with gas has a volume of 185 mL and a pressure of 310 mm Hg. The desired new volume is 74.0 mL. What is the required new pressure? 124 mm Hg 44 mm Hg 775 mm Hg 0.00129 mm Hg

Answers

The answer is 124 mm hg

What is the main function of a telescope?It brings scientists closer to distant objects.

It magnifies light received from distant objects.

It measures the temperature of distant objects.

It measures the wavelengths of incoming light rays

Answers

Explanation :

Telescope is an instrument which is used to magnify distant objects bright, consistent and large.

The function of an ideal telescope must be :

Magnification
Resolution
Power of gathering of light

There are many types of Telescope like:

X ray telescope
Optical telescope
Ultraviolet telescope etc

Hence, the correct option is (b) " It magnifies light received from distant objects ".

It magnifies light received from distant objects.

A ball is thrown horizontally from a 28-meter building with a velocity of 5.5 m/s. How far does the ball land from the base of the building? A) 56 m B) 49 m C) 35 m D) 42 m