It is class 12th physics questions can anyone help me

A train with proper length L has clocks at the front and back. A photon is fired from the front to the back. Working in the trai

tamaranim1 [39]

Explanation:

In train's rest frame, the speed of photon is $c$ and the proper length of the train is $L$ . The time taken by the photon to cross the train is $t=\frac{L}{c}$

In ground frame, the speed of the photon is given as follows:

$v_{x}=\frac{v_{x}+v}{1+\frac{v_{x} \cdot v}{c^{2}}}$

$=\frac{c+v}{1+\frac{c v}{c^{2}}} \\=c$

The speed of light or photon remains same in every frame of reference.

Now, the speed of train is very less as compared to the speed of photon so that $v$ So that, $\frac{v}{c} \ll 1$

The length contraction in the ground frame is given as follows:

$L^{\prime}=L \sqrt{1-\frac{v^{2}}{c^{2}}}$

$=L$

Time taken by the photon to travel the length of the train in ground frame is .

7 0

3 years ago

(Score for Question 4: Click or tap here to enter text of 4 points)

astra-53 [7]

The time of motion of the ball from the vertical height is independent of the horizontal velocity.

Horizontal moving projectiles is not affected by gravity and the initial velocity is equal to the final velocity.

The time of motion of ball dropped from a vertical height is calculated as follows;

$h = v_0_yt \ + \ \frac{1}{2} gt^2\\\\$

where;

h is the vertical height
t is the time of motion
g is acceleration due to gravity
$v_0_y$ is the initial vertical velocity

From the equation above, we can conclude that time of motion of the ball from the vertical height is independent of the horizontal velocity.

If there is variation in drop time, it could be as a result of applied force when the ball is dropped. This applied force influences the initial velocity which in turn alters the drop time.

Generally, horizontal moving projectiles is not affected by gravity and the initial velocity is equal to the final velocity.

Learn more about horizontal and vertical velocity here: brainly.com/question/14354319

7 0

2 years ago

A unit of time sometimes used in microscopic physics is the "shake". One shake equals 10−8 s.

Lady_Fox [76]

Answer:

(a) There are 3.17 times more shakes in a second than seconds in a year.

(b) Humans have existed for 9067.72 universe seconds.

Explanation:

(a) First we calcule how many seconds are in a year. One year have 365 days, one day has 24 hours, one hour has 60 minutes and one minute has 60 seconds, so:

$60s*60*24*365=3.1536*10^7s$