All categories

3 years ago

I've had several mental breakdowns please help me

Physics

1 answer:

sesenic [268]3 years ago

4 0

Answer:

The efficiency of the system is 63.7 %

Explanation:

Given;

input power of the motor, = 1.5 kW = 1,500 W

mass of the car lifted, m = 1300 kg

height through which the car was lifted, h = 1.8 m

time, t = 24 s

The output power of the motor is calculated as;

Output Power = F x v

= (mg) x (d/t)

= (1300 x 9.8) x (1.8 / 24)

= 12,740 x 0.075

= 955.5 W

The efficiency of the system is calculated as;

$E = \frac{0utput \ power}{1nput \ power} \times \ 100\%\\\\E = \frac{955.5}{1500} \times \ 100\% \\\\E = 63.7 \ \%$

The correct answer is 63.7%

You might be interested in

Which of the following terms refers to the amount of heat needed to change 1 kg of a substance from a liquid to a gas at its boi

Nataly [62]

It's B I thinkkkkkkkk

8 0

4 years ago

If the designers of submarines do not appropriately account for hydrostatic pressure,

andre [41]

Answer:

A) the pressure could crush the submarine

Explanation:

The submarines are mainly used for defense purposes.
In world war 1 and 2 the submarines played a vital role in the war.
The submarines work according to the principle of buoyancy.
According to this principle, when seawater is filled inside the tank in a required amount, the submarines sink.
When the seawater is expelled, the submarine rises to above the sea.
Most of the time, it dives deep into the sea, the hydrostatic pressure should be taken into account.
If the hydrostatic pressure is not considered, the pressure could crush the submarine.

7 0

3 years ago

Explain why the intensity of the light in a flashlight beam decreases as the flashlight moves farther away.

Karolina [17]

Ir=Initial Intensity/Area of spread=Io4πr2
Ir∝1r2

It is seen from this expression that intensity is inversely proportional to the square of the distance. As we move away from the light source the intensity decreases at the rate of square of the distance from the source.

Brightness being the perception of intensity. more the intensity more bright the object is perceived and vice versa.

7 0

3 years ago

A horizontal spring has spring constant k = 360 N/m. First, compress the spring from its uncompressed length (x = 0) to x = 11.0

mixas84 [53]

Here we can say that by energy conservation principle

Elastic potential energy of spring will convert into kinetic energy of the block

so here we will have

$\frac{1}{2} kx^2 = \frac{1}{2}mv^2$

we also know that

k = 360 N/m

x = 11 cm

m = 1.85 kg

now we will use all in above equation

$\frac{1}{2}\times 360\times (0.11)^2 = \frac{1}{2}\times (1.85) v^2$

$4.356 = 0.925 v^2$

$v^2 = 4.71$

$v = 2.17 m/s$

so it will move with speed 2.17 m/s after separating from spring

7 0

3 years ago

Read 2 more answers

What would you need to know to calculate the angular momentum of a man on a Ferris wheel?

valentinak56 [21]

The angular momentum calculated with respect to the axis of rotation of an object is given by:
$L=mvr$
where m is the object's mass, v is its tangential speed, and r is its distance from the axis of rotation.

In case of a man on a Ferris wheel, we need to have these quantities in order to calculate his angular momentum. These quantities corresponds to:
- m, the mass of the man
- v, the tangential speed of the wheel at its edge
- r, the radius of the wheel

It is possible to calculate the angular momentum even if we don't know v, the tangential speed. In this case, we need to know at least the angular velocity $\omega$ (because from this relationship we can find the tangential speed: $v=\omega r$ ) or the period of rotation of the wheel, T (because we can find the angular velocity from it: $\omega= \frac{2 \pi}{T}$ ).

4 0

4 years ago