This is called average speed.Its really simple
Answer:
the wavelength is 9.8 meters
Explanation:
We can use the relationship:
Velocity = wavelenght*frequency.
Initially we have:
wavelenght = 4.9m
velocity = 9.8m/s
then:
9.8m/s = 4.9m*f
f = 9.8m/s/4.9m = 2*1/s
now, if the velocity is doubled and the frequency remains the same, we have:
2*9.8m/s = wavelenght*2*1/s
wavelenght = (2*9.8m/s)*(1/2)s = 9.8 m
Answer:
Explanation:
Impulse of reaction force of floor = change in momentum
Velocity of impact = √ 2gh₁
= √ 2 x 9.8 x 1.5 = 5.4 m /s.
velocity of rebound = √2gh₂
= √ 2x 9.8 x 1
= 4.427 m / s.
Initial momentum = .050 x 5.4 = .27 kg m/s
Final momentum = .05 x 4.427 = .22 kg.m/s
change in momentum = .27 - .22 = .05 kg m/s
Impulse = .05 kg m /s
Impulse = force x time
force = impulse / time
.05 / .015 = 3.33 N.
kinetic energy = 1/2 m v²
Initial kinetic energy = 1/2 x .05 x 5.4²
= 0.729 J
Final Kinetic Energy =1/2 x .05 x 4.427²
= 0.489 J
Change in Kinetic energy =0 .24 J
Lost kinetic energy is due to conversion of energy into sound light etc.
Answer:
Explanation:
Given
Initial Intensity of light is S
when an un-polarized light is Passed through a Polarizer then its intensity reduced to half.
When it is passed through a second Polarizer with its transmission axis 
here 
When it is passed through third Polarizer with its axis 
to first but 
to second thus 
When middle sheet is absent then Final Intensity will be zero
Answer:
d. Not enough information is given to answer this question.
Explanation:
From first law of thermodynamics
Q= W + ΔU
Q=Heat ,W= Work , ΔU=Change in internal energy
If work done by the gas :
It means that W and Q both are positive
Q- W = ΔU
Ii Q > W ,then temperature of the gas will increase.
If Q< W ,Then temperature of the gas will decreases.
If work done on the gas:
Q positive but W will be negative
Q- W = ΔU
Q= W or Q>W or Q< W ,then temperature of the gas will increase.
There are three cases because they did not give any information about the work.That is why option d is correct.
