Gravity is trying to push the car down the hill. It takes more power to overcome that push of gravity. Unless you give the car more gas it will slow down.
A drop in speed while going uphill is normal for most vehicles. If the speed is more than 20 mph slower than when first ascending the hill, there could still be a problem with the transmission or an oxygen sensor.
Gravity if going uphill. Friction.
you stand and pedal like what you would do when going uphill
I would suppose it would matter if you were going uphill or downhill.
I would check the point gap and timing first. If that does not correct it, I would check the carburetor float level.
Once you have achieved highway speed, you would stay in the highest gear, except for steep uphill or downhill grades.
Is the vehicles transmission downshifting to a lower gear as you go uphill? If not, that would be your first place to look. After that I would suspect that your engine timing is not autmatically advancing as it should be.
The engine works hard and produces a lot more heat than when the car is driven on a leveled road. The car is usually driven slower on the uphill and there isn't as much air cooling the radiator. But the main reason it overheats is that the cooling system is malfunctioning.
Not downshifting properly Plugged catalytic converter Needs tune-up (new plugs)
It really depends on how fast you're going. If you are driving slower, it would take you longer, and if you drive faster, then it won't take as long. Four minutes at 60 mph.
20
If the slope is 'uphill' then the car is going faster