where is halfway between newcastle and london
The northeastern coast of South Carolina, roughly halfway between Wilmington, NC and Charleston, SC
East coast usa
Valdosta, GA
It is between Miramar Beach, FL and Panama City Beach FL on the northern Gulf Coast of FL.
around the coast of Africa
The halfway points are the points which mark the half distance covered by the flight. These lie in the mid of both the above mentioned places. These points change for different locations. Halfway points for the above mentioned places are - Sri Lanka.
The difference is that a coast is the edge of a piece of land where it meets a large body of water. Whereas a beach is a flat area (not necessarily on the coast) where land meets water, usually sandy or pebbly.
The Virginia/North Carolina border
It would be close to Greenland, just off its west coast.
If you swing south, your halfway point along the coast would be around Bournemouth. If you swing north, your halfway point along the coast would be Bristol, which is less scenic but it's a direct shot on the M4 and M5.
The halfway point is Burnsville, WV. That is on roughly the same latitude as Lewes on the coast of Delaware.