Answer:
Explanation:
The acceleration of the ball would be due to the downward force of gravity, 9.8m/s^2. In order to find the displacement given that interval of time, you have to use the corresponding kinematic formula:

The initial velocity was given, the time was given, and the acceleration was given. Therefore:


To find the required time given a desired final velocity, we can use:




Explanation:
The separation between the interference fringes on the screen increases because
the distance of the screen from the slit is increased. Therefore option (a) is correct.
The separation between the interference fringes on the screen increases because the distance of the screen from the slit is increased, which is contradictory.
Therefore option (b) is incorrect.
The separation between the interference fringes on the screen increases because the distance of the screen from the slit is increased, which is contradictory. Therefore option (c) is incorrect.
The separation between the interference fringes on the screen increases because the distance of the screen from the slit is increased, which is contradictory. Therefore option (d) is incorrect.
The separation between the interference fringes on the screen increases because the distance of the screen from the slit is increased, which is contradictory.
Therefore option (e) is incorrect.
The increase in gravitational potential energy for an object of mass m is given by

where

is the increase in altitude of the object.
In our problem, m=3.0 kg,

and

(approximated value), so we have