A laser beam is incident on two slits with a separation of 0.215 mm, and a screen is placed 5.45 m from the slits. an interferen
1 answer:
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For this case it is necessary to consider the assessments made between collisions of 'immovable' objects. In this case the earth is the immovable object or at least, it is approached by its mass. Considering the case of an inflatable ball of mass m that travels at a speed v towards the ground, it hits the floor and bounces with speed -v (Negative). The earth does not move, however, the momentum of the ball has changed by 2mv since the speed went from positive to negative. Applying the conservation of the momentum we know that the change of the momentum on the fly would be given under the function
Considering the direction of the velocities this expression can be rewritten as
Therefore the correct answer would be
C. Only the momentum of the ball is changed by the collision
Answer:
B
Explanation:
Solution:-
- Take a coordinate system as follows:
x: Directed along the ground
y: Directed vertical to ground
- We will assume that the initial vertical and horizontal non-zeroes velocities are given as follows:
- After a ball is thrown it continues a path of parabolic projectile. The motion of the ball can be analyzed in each coordinate system. We will assume that effects of air-resistance are negligible.
- Therefore, only gravity acts on the ball in the vertical direction. We can use kinematic equation of motions to determine the velocity of ball in either ( x-y ) direction at any instant of time ( t ).
- Use first kinematic equation of motion in both x and y directions.
- The accelerations ( ax and ay ) in the direction of each axis are to be determined. We know that the gravity acceleration ( g ) acts in vertical direction or along y-axis ( ay ) and always directed downwards while velocity is directed up. Since, we neglected the effects of air-resistance there is no acceleration in the x-direction ( ax = 0 ) .
- We see that the horizontal velocity of the ball ( vxf ) at any point in time remains equal to the initial horizontal velocity; hence, it is constant throughout the journey.
- However, the velocity of the ball in vertical direction( vyf ) is changing for every unit of time ( t ) under the influence of gravitational acceleration. Hence, it is not constant throughout the journey