Ask question

Ask question

All categories

2 years ago

12

A _____ provides rapid calculus removal by converting very-high-frequency sound waves into mechanical energy and reduces operato

r hand fatigue.

1 answer:

sveticcg [70]2 years ago

8 0

Answer:

The Ultrasonic Scaler

Explanation:

You might be interested in

A plane wall of thickness 0.1 mm and thermal conductivity 25 W/m K having uniform volumetric heat generation of 0.3 MW/m3 is ins

juin [17]

Answer:

The maximum temperature is 90.06° C

Explanation:

Given that

t= 0.1 mm

Heat generation

$q_g=0.3\ MW/m^3$

Heat transfer coefficient

$h=500\ W/m^2K$

Here one side(left side) of the wall is insulated so the all heat will goes in to right side .

The maximum temperature will at the left side.

Lets take maximum temperature is T

Total heat flux ,q

$q=q_g\times t$

$q=0.3\times 1000000\times 0.1 \times 10^{-3}\ W/m^2$

$q=30\ W/m^2$

So the total thermal resistance per unit area

$R=\dfrac{t}{K}+\dfrac{1}{h}$

$R=\dfrac{0.1\times 10^{-3}}{25}+\dfrac{1}{500}$

R=0.002 K/W

We know that

q=ΔT/R

30=(T-90)/0.002

T=90.06° C

The maximum temperature is 90.06° C

3 0

3 years ago

A frame hanging on a wall is held by two cables. The tension in each cable is 30 N, and the cables make an angle of 45° with the

Dimas [21]

Answer: option D) 42.4 N

The weight of the frame is balanced by the vertical component of tension.

W = T sin θ + T sin θ = 2 T sin θ

The tension in each cable is T = 30 N

Angle made by the cables with the horizontal, θ = 45°

⇒ W = 2×30 N × sin 45° = 2 × 30 N × 0.707 = 42.4 N

Hence, the weight of the frame is 42.4 N. Correct option is D.

6 0

3 years ago

Suppose that the half-life of an element is 1000 years. How many half-lives will it take before one-eighth of the original sampl

34kurt

Answer:

3

Explanation:

The half-life of a radioactive isotope is the time it takes for the mass of the sample to halve.

This can be rewritten as follows:

$m(t) = m_0 (\frac{1}{2})^n$

where

m(t) is the mass of the sample at time t

m0 is the original mass of the sample

n is the number of half-lives that passed

We see that if we take n=3, the amount of original sample left is

$m(t) = m_0 (\frac{1}{2})^3 = m_0 (\frac{1}{8})$

So 3 (3 half-lives) is the correct answer.

3 0

3 years ago

Read 2 more answers

an empty propane tank dropped from a hot air balloon hits the ground with a speed of 143.8 m/s. from what height was the tank re

vodomira [7]

What you know:
Vi=0m/s
Vf=143.8m/s
A=-9.8m/s
d=???
Use the equation Vf^2=Vi^2+2A(d)
Rearrange to isolate d: d=Vf^2/2A
d=(143.8)^2/2(-9.8)
d=20678.4/-19.6
d=-1055m
The tank was released from a height of 1055m

8 0

3 years ago

A thin taut string is fixed at both ends and stretched along the horizontal x-axis with its left end at x = 0. It is vibrating i

Fofino [41]

Answer:

(a) Wavelength is 0.436 m

(b) Length is 0.872 m

(c) 11.518 m/s

Solution:

As per the question:

The eqn of the displacement is given by:

$y(x, t) = (1.22 cm)sin[14.4 m^{- 1}x]cos[(166\ rad/s)t]$ (1)

n = 4

Now,

We know the standard eqn is given by:

$y = AsinKxcos\omega t$ (2)

Now, on comparing eqn (1) and (2):

A = 1.22 cm

K = $14.4 m^{- 1}$

$\omega = 166\ rad/s$

where

A = Amplitude

K = Propagation constant

$\omega$ = angular velocity

Now, to calculate the string's wavelength,

(a) $K = \frac{2\pi}{\lambda}$

where

K = propagation vector

$\lambda = \frac{2\pi}{K}$

$\lambda = \frac{2\pi}{14.4} = 0.436\ m$

(b) The length of the string is given by:

$l = \frac{n\lambda}{2}$

$l = \frac{4\times 0.436}{2} = 0.872\ m$

(c) Now, we first find the frequency of the wave:

$\omega = 2\pi f$

$f = \frac{\omega}{2\pi}$

$f = \frac{2\pi}{166} = 26.42\ Hz$

Now,

Speed of the wave is given by:

$v = f\lambda$

$v = 26.419\times 0.436 = 11.518\ m/s$

4 0

3 years ago