Which one of the following is correct? *

Dario, a prep cook at an Italian restaurant, spins a salad spinner and observes that it rotates 20.0 times in 5.00 seconds and t

ziro4ka [17]

Answer:

(a). The acceleration is 8.3 rad/s².

(b). The time is 3.0 sec.

Explanation:

Given that,

Rotation = 20.0 times

Time = 5.00 sec

We need to calculate the angular frequency

Using formula of angular frequency

$\omega_{i}=20\times\dfrac{2\pi}{T}$

put the value into the formula

$\omega_{i}=20\times\dfrac{2\pi}{5.00}$

$\omega_{i}=8.00\pi$

We need to calculate the angular displacement

Using formula of angular displacement

$\theta=6\times2\pi=12\pi$

We need to calculate the angular acceleration

Using equation of angular motion

$\omega_{f}^2-\omega_{i}^2=2\alpha\times\theta$

$0-64\pi^2=2\times12\pi\times\alpha$

$\alpha=-\dfrac{64\pi^2}{24\pi}$

$\alpha=-8.3\ rad/s^2$

Negative sign shows the opposite direction of the motion.

The acceleration is 8.3 rad/s².

We need to calculate the time

Using equation of angular motion

$\omega_{f}-\omega_{i}=\alpha\times t$

$0-8\pi=-8.3t$

$t=\dfrac{8\pi}{8.3}$

$t=3.0\ sec$

The time is 3.0 sec.

Hence, (a). The acceleration is 8.3 rad/s².

(b). The time is 3.0 sec.

4 0

3 years ago

What is the main function of the excretory system?

tiny-mole [99]

Answer: To collect and remove wastes from the body.

Explanation:

The excretory system helps to collect and remove wastes from the body in the form of urine.

6 0

4 years ago

Read 2 more answers

How much work is needed to move an object from one position to another when both positions are located the same distance from th

Vladimir79 [104]

Answer:

The product of the object's weight and the horizontal distance between the two positions.

Explanation:

Work is the product of force and the distance through which this force is moved. The distance moved can be vertical, or horizontal. For two bodies located the same distance from the center of the earth, the work done will be the product of the weight of the product and the horizontal distance between the two positions. If the vertical work is needed, then the work is zero, since there is no height gradient between them.

8 0

4 years ago

A particular person's eardrum is circular, with a diameter of 7.90 mm. How much sound energy (in J) is delivered to an eardrum i

antiseptic1488 [7]

Answer:

$4.90167\times 10^{-17}\ J$

Explanation:

I = Hearing intensity = $1\times 10^{-12}\ W/m^2$

A = Area = $\pi r^2$

d = Diameter = 7.9 mm

r = Radius = $\dfrac{d}{2}=\dfrac{7.9}{2}=3.95\ mm$

Power is given by

$P=IA\\\Rightarrow P=1\times 10^{-12}\times \pi \times (3.95\times 10^{-3})^2\\\Rightarrow P=4.90167\times 10^{-17}\ W$

t = Time the eardrum is exposed to sound = 1 second

Energy is given by

$E=Pt\\\Rightarrow E=4.90167\times 10^{-17}\times 1\\\Rightarrow E=4.90167\times 10^{-17}\ J$

The energy transferred to the eardrum is $4.90167\times 10^{-17}\ J$

3 0

3 years ago

Read 2 more answers

A punter wants to kick a football so that the football has a total flight time of 3.7 s and lands 56m away (measured along the g

Irina18 [472]

The maximum height is 16.8 m

Explanation:

In order to find the maximum height reached by the football, we can just analyze its vertical motion.

The vertical motion of the ball is a free fall motion, affected only by the force of gravity. So it is a uniformly accelerated motion, and we can use suvat equations.

First of all, we notice that the motion of the ball is symmetrical, so the time taken to reach the maximum height is equal to the time needed to fall down: Since the total time of flight is

T = 3.7 s

It means that the time to reach the maximum height is

$t=\frac{T}{2}=\frac{3.7}{2}=1.85 s$