On the change in potential energy
Answer:
a) 
b) 
Explanation:
Part a
For this case we can begin finding the period like this:

Then we know that the centripetal acceleration is given by:

And the velocity is given by:

If we replace this into the acceleration we got:

And we can replace the values and we got:

Part b
For this case we want to find a value of k such that:

Where a = 9.74, so then we can solve for k like this:

Answer:
Explanation:
velocity of projection, vo = 381 m/s
angle of projection, θ = 73.5°
The formula for the range is


R = 8067.4 m
Range in shorten by 34.1 %
So, the new range is
R' = 8067.4 - 34.1 x 8067.4/100
R' = 5316.4 m
Answer: The magnetic field of a bar magnet is strongest at either pole of the magnet. It is equally strong at the north pole compared with the south pole. The force is weaker in the middle of the magnet and halfway between the pole and the center. So it would be D.