Answer:
The correct answer to the question is (A)
When it hits the heavy rope, compared to the wave on the string, the wave that propagates along the rope has the same (A) frequency
Explanation:
The speed of a wave in a string is dependent on the square root of the tension ad inversely proportional to the square root of the linear density of the string. Generally, the speed of a wave through a spring is dependent on the elastic and inertia properties of the string
Therefore if the linear density of the heavy rope is four times that of light rope the velocity is halved and since
v = f×λ therefore v/2 = f×λ/2
Therefore the wavelength is halved, however the frequency remains the same as continuity requires the frequency of the incident pulse vibration to be transmitted to the denser medium for the wave to continue as the wave is due to vibrating particles from a source for example
Answer: 2.92 s
Explanation:
Given
Mass of ball is 
The initial velocity of the ball is 
Velocity after the rebound is 
Force during the contact is 
We know, change in momentum is Impulse
Thus, the force is applied for 2.92 s
Power = work / time = 8000J / 20s = 400W
Answer:
speed of each marble after collision will be 1.728 m/sec
Explanation:
We have given mass of the marble 
Velocity of marble 
Its collides with other marble of mass 25 gram
So mass of other marble 
Second marble is at so 
We have to find the velocity of second marble
From momentum conservation we know that
, here v is common velocity of both marble after collision
So 
v = 1.428 m /sec
So speed of each marble after collision will be 1.728 m/sec
Answer:
c. detecting the gravitational effect of an orbiting planet (The Wobble"") by looking for the Doppler shifts in the star's spectrum
Explanation:
In a solar system the mass of the star and planets affect each other's orbital movements. The center of gravity of a star and a planet is inside the star. This causes the star to be closer and farther from the Earth at different times. Due to this wobble the star appears to be red shifted when it is farther and blue shifted when it is closer.
When the mass of the planet is high, like a hot Jupiter it causes more wobble i.e., change in radial velocity. This makes it easier to detect the planet. The earliest hot Jupiter found by this method is the planet 51 Pegasi b.
