Check your PC for viruses and so caled "jokes".
About up to an hour at max
It takes light exactly one hour to travel in 1 hour.
Depends on the time of year and place. When you are at the equator, the days are exactly 12 hours and the nights are exactly 12 hours.
Exactly 15 km per hour.
At every hour exactly, for example 'the train will leave at 1pm or 2pm and so on - on the hour.
Exactly 1 hour
No.
There are exactly 144,000 seconds in a 40 hour work week. There are 2,400 minutes in 40 hours and 144,000 second in 2,400 minutes.
Cleaning a car.
Exactly 100 miles
one hour
That means to every full hour. Always when the long arm is at the 12.