The Helios probes are notable for having set a maximum speed record among spacecraft at 252,792 km/h (157,078 mi/h or 43.63 mi/s or 70.22 km/s or 0.000234c. (c is short for celerity and is shorthand for speed of light.)
'Top speed' refers to the maximum speed that a vehicle or object can achieve under optimal conditions. It represents the highest rate of travel that can be reached by a particular vehicle or object.
in the summer Olympics of 2010 usain bolt ran a record of 19.9 miles an hourThat's not what the question asked. I believe the Highest speed ever reached by a human was Lee Evans at 28.3 mph. I'd be interested to see what Bolt would be clocked at by, say, a radar gun...
The greatest speed reached by a falling object is known as terminal velocity. This is when the gravitational force pulling the object down is equal to the air resistance acting against it, resulting in a constant speed. Terminal velocity for a human falling through the atmosphere is around 120 mph (200 km/h).
A falling object that has reached its terminal speed no longer accelerates due to air resistance balancing the gravitational force. At terminal speed, the object continues to fall with a constant velocity and no longer gains speed.
The instantaneous speed of the object at its highest point is zero. At that moment, the object is at rest before it starts to fall back down due to gravity.
Terminal velocity is reached when the forces of gravity and air resistance acting on an object are equal, causing the object to no longer accelerate. To measure when an object has reached terminal velocity, you can observe that the object falls at a constant speed without speeding up. This can be done by measuring the object's velocity as it falls and noting when it remains constant.
When a falling object stops speeding up and falls at a constant rate of speed, it has reached its terminal velocity. Terminal velocity occurs when the force of air resistance equals the force of gravity acting on the object, resulting in a balanced and constant downward acceleration.
the highest speed rate was 11 mph, but that was a world record
The universal speed limit for material objects is c : the speed of light in a vacuum.
The instantaneous speed of an object at its highest point when thrown straight up in the air is zero. At the highest point, the object has momentarily stopped moving upwards and is just about to start falling back down due to gravity.
terminal velocity
That question is not very specific. The answer in general is the speed of light. A better question would be to specify what object or thing in respect to what, like what was the fastest speed ever achieved by a manned land vehicle.