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3 years ago

Two ice skaters are at rest, Abby

Physics

2 answers:

nikdorinn [45]3 years ago

8 0

Answer:68.4kg

Explanation:

alekssr [168]3 years ago

6 0

Answer:

This is the answer

Explanation:

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Use the fact that the speed of light in a vacuum is about 3.00 × 108 m/s to determine how many kilometers a pulse from a laser b

Morgarella [4.7K]

The first thing that needs to be done is to find everything in the same units. 12 hours becomes 43200 seconds. Then find the distance traveled by light in that amount of time. Using the formula v=d/s, manipulate it so it looks like d=v*s. Then plug in the values: d=(3x10^8)*43200, d=1.3x10^13m. But you need to find this in kilometers. To do this, simply divide your answer by one thousand. Thus, a laser beam would travel 1.3x10^10 kilometers in 12 hours.

5 0

3 years ago

At high speeds, a particular automobile is capable of an acceleration of about 0.540 m/s^2. At this rate, how long (in seconds)

Mama L [17]

Answer:

t = 6.68 seconds

Explanation:

The acceleration of the automobile, $a=0.54\ m/s^2$

Initial speed of the automobile, u = 91 km/hr = 25.27 m/s

Final speed of the automobile, v = 104 km/hr = 28.88 m/s

Let t is the time taken to accelerate from u to v. It can be calculated as the following formula as :

$t=\dfrac{v-u}{a}$

$t=\dfrac{28.88-25.27}{0.54}$

t = 6.68 seconds

So, the time taken by the automobile to accelerate from u to v is 6.68 seconds. Hence, this is the required solution.

5 0

3 years ago

1. Two blocks travel along a level frictionless surface. Block A is initially moving to the right at 5.0 m/s, while block B is i

ad-work [718]

Answer: 2.67 m/s

Explanation:

Given

Mass of block A is $m_a=2\ kg$

mass of block B is $m_b=3\ kg$

The initial velocity of block A $u_a=5\ m/s$

the initial velocity of block B is $u_b=0$

After collision velocity of block A is $v_a=1\ m/s$

Conserving momentum

$m_au_a+m_bu_b=m_av_a+m_bv_b\\\\2\times 5+3\times0=2\times 1+3\times v_b\\\\v_b=\dfrac{8}{3}=2.67\ m/s$

The momentum of block A after the collision is $P_a=2\times 1=2\ kg.m/s$

Therefore, there is no change in sign.

6 0

3 years ago

If a high jumper needs to make his center of gravity rise 1.50 m, how fast must he be able to sprint? Assume all of his kinetic

sergiy2304 [10]

Answer:

v = 5.42 m/s

Explanation:

given,

height of the jumper = 1.5 m

velocity of sprinter = ?

kinetic energy can be transformed into potential energy

$m g h = \dfrac{1}{2}mv^2$

$g h = \dfrac{1}{2}v^2$

$v =\sqrt{2gh}$

$v =\sqrt{2\times 9.8 \times 1.5}$

v = 5.42 m/s

Speed of the sprinter is equal to v = 5.42 m/s

7 0

3 years ago

What is the wavelength, in nm, of the line in the hydrogen spectrum when one n value is 3 and the other n value is 6?

iren [92.7K]

Answer:

$\lambda=1090nm$

Explanation:

Rydberg formula is used to calculate the wavelengths of the spectral lines of many chemical elements. For the hydrogen, is defined as:

$\frac{1}{\lambda}=R_H(\frac{1}{n_1^2}-\frac{1}{n_2^2})$

Where $R_H$ is the Rydberg constant for hydrogen and $n_1$ , $n_2$ are the lower energy state and the higher energy state, respectively.

$\frac{1}{\lambda}=1.10*10^{7}m^{-1}(\frac{1}{3^2}-\frac{1}{6^2})\\\frac{1}{\lambda}=9.17*10^{5}m^{-1}\\\lambda=\frac{1}{1.09*10^{6}m^{-1}}\\\lambda=1.09*10^{-6}m*\frac{10^{9}nm}{1m}\\\lambda=1090nm$

4 0

3 years ago