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andrey2020 [161]

3 years ago

6

Question 6 options: When a cannon is fired, the projectile moves forward. According to Newton's 3rd law, the cannon will want to

travel
PLEASE HELP!!!!!!!
question will give you 20PTS!!!

1 answer:

anygoal [31]3 years ago

5 0

Backwards i just took the test

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What is the length of a pendulum with a period of one second?

worty [1.4K]

Answer:

A simple pendulum with a period of 1 second will have a length of 0.25 meters or 25 centimeters

Explanation:

hope it helps u☺☺

7 0

3 years ago

Consider a particle with unit charge q, and mass m, in a constant magnetic field B directed along the positive z–axis. The parti

max2010maxim [7]

Answer:

it must be helical motion in which the charge particle will move uniformly along z axis and simultaneously it will move in circular path in xy plane.

Explanation:

Magnetic field is along z axis while velocity is in x-z plane

so we will have

$F = q(\vec v \times \vec B)$

so here we can say

$F = q(u\hat i + w\hat k) \times (B \hat k)$

so we will have

$F = quB(-\hat j)$

so here the net force on the charge is perpendicular to its x directional velocity along - Y direction

So due to this component of motion it will move along a circle while other component of the motion will remain uniform always

So here it is combination of two parts

1) Uniform circular motion

2) Uniform motion

So we can say that it must be helical motion in which the charge particle will move uniformly along z axis and simultaneously it will move in circular path in xy plane.

4 0

3 years ago

An electric car has a battery that can hold 16 kwh of energy. if the battery is designed to operate at 340 v, how many coulombs

Zanzabum

charge needed= 169412 C

Explanation:

energy stored in the battery= 16 KWh= 16 (1000 W)(3600 s)= 5.76 x 10⁷ J

Energy stored is given by U= q V

q= charge

V= voltage= 340 V

so 5.76 x 10⁷ = q (340)

q= 169412 C

4 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

To determine athletes body fat, there are weighed first in air and then again while they are completely underwater. It is found

rodikova [14]

Answer:

1065 Kgm-3

Explanation:

We can determine the relative density of the athlete from the formula;

Relative density of athlete = weight of athlete in air/upthrust on athlete

Since weight of athlete in air= 690 N

Weight of athlete in water = 42 N

Upthrust on athlete= weight in air - weight in water

Upthrust on athlete= 690 N - 42 N = 648 N

Relative density of athlete= 690 N / 648 N

Relative density of athlete= 1.065

Therefore, average density of the athlete= relative density × density of water = 1.065 × 1000 Kgm-3 = 1065 Kgm-3

4 0

4 years ago