Answer:
Explanation:
My speed after the interaction will depend upon the impulse the ball will make on me . Now impulse can be expressed as follows
Impulse = change in momentum
change in momentum in the ball will be maximum when the ball bounces back with the same velocity which can be shown as follows
change in momentum = mv - ( - mv ) = 2mv
So when ball is bounced back with same velocity , it suffers greatest impulse from my hand . In return , it reacts with the same impulse on my hand pushing me with greatest impulse according to third law of motion. this maximizes my speed after the interaction.
Answer:
Explanation:
Bohr's energy expression is as follows
E_n = 13.6 z² /n² where z is atomic no and n is principal quantum no of the atom .
z for helium is 2 and for ionised atom is 5 . Let energy of n₁ level of He is equal to energy level n₂ of ionised atom
so
13.6 x 2² / n₁² = 13.6 x 5² / n₂²
n₁ / n₂ = 2/5 , ie 2nd energy level of He matches 5 th energy level of ionised atom .
For quantum numbers less than or equal to 9 , If we take n₁ = 8 for He
Putting it in the equation above
2² / 8² = 5² / n₂²
n₂ = 5 x 8 / 2
= 20 .
energy
= - 13.6 x2² / 8²
= - 0.85 eV .
The acceleration is given as:
a = g sin(30°) where g is the gravitational acceleration
For g = 10 m/s^2, we get
a = 10 sin(30°) = 10 * 1/2 = 5 m/s^2
The question is missing, but I guess the problem is asking for the distance between the cliff and the source of the sound.
First of all, we need to calculate the speed of sound at temperature of

:

The sound wave travels from the original point to the cliff and then back again to the original point in a total time of t=4.60 s. If we call L the distance between the source of the sound wave and the cliff, we can write (since the wave moves by uniform motion):

where v is the speed of the wave, 2L is the total distance covered by the wave and t is the time. Re-arranging the formula, we can calculate L, the distance between the source of the sound and the cliff:
The second law of thermodynamics states that whenever energy changes occur, DISORDER always increases.