All categories

4 years ago

Name two specific contributions bohr made to our understanding of atomic structure

Physics

1 answer:

MAXImum [283]4 years ago

6 0

Https://answers.yahoo.com/question/index?qid=20120227184717AAzEq8g

You might be interested in

Can someone pleaseeee answer this !!!!!!

LenaWriter [7]

Answer:

The person with locked legs will experience greater impact force.

Explanation:

Let the two persons be of nearly equal mass (say m)

The final velocity of an object (person) dropped from a height H (here 2 meters) is given by,

$v=\sqrt{2gH}$

( $g$ = acceleration due to gravity)

which can be derived from Newton's equation of motion,

$v^2=u^2+2aS$

Now, the time taken (say $t$ ) for the momentum ( $mv$ ) to change to zero will be more in the case of the person who bends his legs on impact than who keeps his legs locked.

We know that,

$Force=\frac{\Delta(mv)}{t}$

Naturally, the person who bends his legs will experience lesser force since $t$ is larger.

3 0

3 years ago

Assume a change at the source of sound reduces the wavelength of a sound wave in air by a factor of 3.

noname [10]

Explanation:

The speed of a wave is given by :

$v=f\lambda$ ......(1)

(i) Here, the wavelength of a sound wave in air reduces by a factor of 3. Equation (1) becomes :

$\lambda=\dfrac{v}{f}$

Wavelength and frequency are inversely proportional to each other. So, if wavelength of a sound wave in air reduces by a factor of 3, then the frequency will increases by a factor of 3.

(ii) It remains the same.

8 0

3 years ago

HELP

Sergeu [11.5K]

Answer:

The answer is: To accelerate an object the force applied to the object has to increase.

Explanation:

the acceleration of an object increases with increased force and decreases with increased mass.

3 0

3 years ago

What is the most appropriate SI unit to express the speed of a cyclist in a 10-km race? km/s cm/h km/h mm/s

Murljashka [212]

You sure wouldn't want something like cm/s or (yikes cm/hr). You want a reasonable number for sports usually between 0 and 100

Km / hour would be a good choice.

The next town to where I live is 25 km away. On a good day, I can make it there in about 3/4 of an hour.

Speed = 25 km / 0.75 hour = 33.3 km/hour. That's actually a little fast most of the time. But you should understand what I mean.

5 0

3 years ago

A 392 N wheel comes off a moving truck and rolls without slipping along a highway. At the bottom of a hill it is rotating at 24

alex41 [277]

Answer:

h=12.41m

Explanation:

N=392

r=0.6m

w=24 rad/s

$I=0.8*m*r^{2}$

So the weight of the wheel is the force N divide on the gravity and also can find momentum of inertia to determine the kinetic energy at motion

$N=m*g\\m=\frac{N}{g}\\m=\frac{392N}{9.8\frac{m}{s^{2}}}$

$m=40kg$

moment of inertia

$M_{I}=0.8*40.0kg*(0.6m} )^{2}\\M_{I}=11.5 kg*m^{2}$

Kinetic energy of the rotation motion

$K_{r}=\frac{1}{2}*I*W^{2}\\K_{r}=\frac{1}{2}*11.52kg*m^{2}*(24\frac{rad}{s})^{2}\\K_{r}=3317.76J$

Kinetic energy translational

$K_{t}=\frac{1}{2}*m*v^{2}\\v=w*r\\v=24rad/s*0.6m=14.4 \frac{m}{s}\\K_{t}=\frac{1}{2}*40kg*(14.4\frac{m}{s})^{2}\\K_{t}=4147.2J$

Total kinetic energy

$K=3317.79J+4147.2J\\K=7464.99J$

Now the work done by the friction is acting at the motion so the kinetic energy and the work of motion give the potential work so there we can find height

$K-W=E_{p}\\7464.99-2600J=m*g*h\\4864.99J=m*g*h\\h=\frac{4864.99J}{m*g}\\h=\frac{4864.99J}{392N}\\h=12.41m$

6 0

3 years ago