Would lifting a 1 kg block 1 meter off the ground be work? Yes or No

Koi is climbing through a crevice and places her feet so that her body is perpendicular as shown below she then rest in this spo

Anastaziya [24]

The type of force that Koi is demonstrating in this position would be: <span>static friction
</span><span>static friction is a type of force that created when a stationary object is placed on the surface where it's resting. It also defined the amount of force you need to overcome before you could move the object</span>

3 0

4 years ago

A wind turbine is rotating at 15 rpm under steady winds flowing through the turbine at a rate of 42,000 kg/s. The tip velocity o

zzz [600]

Answer:

a) 5.22 m/s

b) 31.4 %

Explanation:

f = rotating speed = 15 rpm = 15/60 =0.25 rps

m = Mass flow rate of air = 42000 kg/s

v = Tip velocity = 250 km/h = 250/3.6 = 69.44 m/s

W = Work output = 180 kW

A = Swept area of wind turbine

r = Radius of wind turbine

η = Efficiency

$r=\frac{v}{2\pi f}\\\Rightarrow r=\frac{250\div 3.6}{2\pi 0.25}=\frac{250}{1.8\pi}$

$A=\pi r^2\\\Rightarrow A=\pi\left(\frac{250}{1.8\pi}\right)^2\\\Rightarrow A=\left(\frac{250}{1.8}\right)^2\frac{1}{\pi}$

$m=\rho V\\\Rightarrow m=\rho vA\\\Rightarrow v=\frac{m}{\rho A}\\\Rightarrow v=\frac{42000}{1.31 \left(\frac{250}{1.8}\right)^2\frac{1}{\pi}}\\\Rightarrow v=5.22\ m/s$

∴ The average velocity of the air is 5.22 m/s

$E=m\frac{v^2}{2}=42000\frac{5.22^2}{2}\\\Rightarrow E=572538.92$

$\eta=\frac{W}{E}=\frac{180000}{572538.92}\\\Rightarrow \eta =0.314$

∴ Conversion efficiency of the turbine is 0.314 or 31.4 %

7 0

3 years ago

Read 2 more answers

Difference between displacement time graph and velocity time graph.

marishachu [46]

Answer:

A d-t graph's slope is equivalent to the speed and direction while a v-t graph's slope is equal to its acceleration. A constant slope for a d-t graph means that the speed is constant. The area underneath a v-t graph would be its distance.

Explanation:

7 0

2 years ago

A pebble is dropped from rest from the top of a tall cliff and falls 53.4 m after 3.3 s has elapsed. How much farther does it dr

jeka94

Answer:

426.84 m

Explanation:

initial velocity u = 0

time t = 3.3 s

distance travelled s = 53.4 m

acceleration due to gravity = g

s = ut + 1/2 g t²

53.4 = 0 + 1/2 g x 3.3²

g = 9.8 m /s²

For the whole length of fall

distance travelled = h

total time = 6.6 + 3.3 = 9.9 s

h = ut + 1/2 g t²

u again = 0

h = .5 x 9.8 x 9.9²

= 480.24 m

distance travelled in last 6.6 s

= 480.24 - 53.4

= 426.84 m

6 0

3 years ago

If 32g of kerosene of densities of 0.80gcm-3 are mixed with 8g of water, what is the densities of the resulting

kvasek [131]

Answer:

volume = 8 cm^3 + 32 g / 0.8 g/ cm^3 = 48 cm^3

mass = 32 + 8 = 40 g

40 g / 48 cm^3

Explanation:

4 0

3 years ago