Answer:
Explanation:
a ) Momentum of first cart = mass x velocity
= 3 x 4.6 =+13.8 kg m /s
Momentum of second cart = 1.3 x - 1.9 = - 2.47 kg m /s
Total momentum = 13.8 - 2.47
= +11.33 kg m /s
b )
Let the velocity of first cart be v at the moment when second cart was at rest
total momentum = 3 x v + 0 = 3 v
Applying conservation of momentum law
3 v = +11.33
v = +3.77 m /s
The speed at which the objects were attracted to each other determined by the gravitational pull.
<h3>What is gravity?</h3>
The force of attraction felt by a person at the center of a planet or Earth is called as the gravity or gravitational pull.
The gravitational force, Fg is the attractive force exerted by the Earth on the object that is equal to the mass of the object times the gravitational acceleration.
When the two objects are attracted, the speed with which they are moving toward each other depends on the strength of the pull force. This pull force is the gravitational pull.
Thus, the speed at which the objects were attracted to each other determined by the gravitational pull.
Learn more about gravity.
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Answer: The ball (option A)
Explanation: change in momentum is defined by the formulae m(v - u) where m = mass of object, v = final velocity and u = initial velocity.
For the ball, it hits the ground and bounces back with the same speed, that's final velocity equals initials (v = - u)
Change in momentum = m( -u- u) = m(-2u) = m(-2u) = -2mu
For the clay, it final velocity is zero since it sticks to the floor, hence (v =0)
m(v - u) = m(0 - u) = - mu.
-2mu (change in momentum from the ball) is greater than - mu ( change in momentum of clay)
If the distance to a point source of sound is doubled, by a multiplicative factor of 4, the intensity changes.
Intensity of sound is the sound which is perpendicular to sound wave propogation per unit area. It is dependent on the Surface of source sound.
Intensity is the Power per unit area. Its SI unit is Watt/m².
As we move away from a source of sound, the sound starts to diminish. This is due to the decreasing sound intensity with distance.
It can also be understood by the fact that on increasing distance, the Power radiated by the source spreads over a larger area. Hence, the Intensity decreases gradually.
Since, Intensity is proportional to the square of the distance.
Hence, on doubling the distance, Intensity reduces to one fourth of the initial intensity or reduces by a multiplicative factor of 4.
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