running watches speed and distance image
trickyeric
So what I'm asking is if a vessel is traveling at 99% light speed and fires a rocket or cannon. (any projectile) What is that projectiles speed? Since nothing can travel faster than light speed how will this projectile accelerate out of the vessel?
Answer
If you were in a train travelling at 100m/h and there was a bystander watching, relative to the bystander you would be moving at 100m/h. However relative to the train you wouldn't be moving. This is why we say motion MUST be described relative to something.
If you threw a ball while on the train at 5m/h, to the bystander the ball would be measured at 105m/h. i.e the speed of the train + the speed of the ball, However relative to you, the ball would be moving at 5m/h.
If you were on this train moving at 100m/h, and the headlights were turned on, what speed do you think the bystander would measure the photons at? if you are using the velocity adding technique this would be wrong, it was demonstrated clearly that when dealing with things to do with light speed, the velocity of light is ALWAYS the same. So you in the train would measure the same speed of light as the bystander on the train tracks...surely this doesn't make sense. But it does.
Likewise if a vessel was moving at 99% the speed of light, and it shot a projectile, you would think due to the velocity adding technique that as the projectile was already travelling at 99% the speed of light, then when you add the velocity of the projectile itself it would be moving faster than light. Except this doesn't happen, the projectile would not move faster than the speed of light, the velocity adding method doesn't apply when dealing with things near light speed.
Light will always be faster than the projectile, and the reason this would be achieved is through time dilation and length contraction. The projectile and the vessel would be shortened in the direction of movement. And relative to a stationary observer time on the vessel would have slowed down tremendously. As we all know speed = Distance/Time. With length contraction + the effects of time dilation, no matter how fast the vessel or the projectile is travelling the speed would always be worked out to be smaller than the speed of light. Why? because like I explained, time dilation makes it so that a body moving at or close to the speed of light time will slow down, for the inhabitants of the vessel it would seem that NOTHING has changed and that time was progressing as normal, but to an observer it would be clear that the time on the vessel would be moving much slower relative to a stationary clock. The length contraction of the vessel and the projectile would mean they would cover a smaller distance in length than they would normally, combined with time running slower, Speed=Dist/Time would work out to be smaller than the speed of light.
If you were in a train travelling at 100m/h and there was a bystander watching, relative to the bystander you would be moving at 100m/h. However relative to the train you wouldn't be moving. This is why we say motion MUST be described relative to something.
If you threw a ball while on the train at 5m/h, to the bystander the ball would be measured at 105m/h. i.e the speed of the train + the speed of the ball, However relative to you, the ball would be moving at 5m/h.
If you were on this train moving at 100m/h, and the headlights were turned on, what speed do you think the bystander would measure the photons at? if you are using the velocity adding technique this would be wrong, it was demonstrated clearly that when dealing with things to do with light speed, the velocity of light is ALWAYS the same. So you in the train would measure the same speed of light as the bystander on the train tracks...surely this doesn't make sense. But it does.
Likewise if a vessel was moving at 99% the speed of light, and it shot a projectile, you would think due to the velocity adding technique that as the projectile was already travelling at 99% the speed of light, then when you add the velocity of the projectile itself it would be moving faster than light. Except this doesn't happen, the projectile would not move faster than the speed of light, the velocity adding method doesn't apply when dealing with things near light speed.
Light will always be faster than the projectile, and the reason this would be achieved is through time dilation and length contraction. The projectile and the vessel would be shortened in the direction of movement. And relative to a stationary observer time on the vessel would have slowed down tremendously. As we all know speed = Distance/Time. With length contraction + the effects of time dilation, no matter how fast the vessel or the projectile is travelling the speed would always be worked out to be smaller than the speed of light. Why? because like I explained, time dilation makes it so that a body moving at or close to the speed of light time will slow down, for the inhabitants of the vessel it would seem that NOTHING has changed and that time was progressing as normal, but to an observer it would be clear that the time on the vessel would be moving much slower relative to a stationary clock. The length contraction of the vessel and the projectile would mean they would cover a smaller distance in length than they would normally, combined with time running slower, Speed=Dist/Time would work out to be smaller than the speed of light.
Why does it seem harder to run outside than on my treadmill?
Q. When I'm at home, I go from walking to running and then back to walking in half an hour, then I use the bike for ten minutes. When I run outside, I get tired right when I start. I can only run up a small street at a time. I only end up being outside for 15 minutes, and most of that time was spent walking. Why is it harder for me to run outside?
Answer
When it comes to treadmill and road running and which is easier and better, some people say treadmill, some say roads... personal choices really I am afraid to say. Both have good and bad points. For example I missed 2 weeks road running in the winter - too icy!
Physically treadmill running is easier
I have read a few studies (proper scientific ones measuring oxygen use and things like that) and the results suggest that road running is about 10% harder than a treadmill. To keep the sums easy that means that if you want to have the same effect as a running at 10km/h on the road you need to put the treadmill at 11km/h (see I like easy sums).
There are actually more differences than you would imagine from road running and treadmill running to account for this. One of the big ones is that the treadmill is flat - roads go up and down, the other main one is wind resistance - this counts for a large difference. The treadmill surface is springy and that bounces you back when you land on it (but also reduces the stress on your body) where roads arn't so springy so are harder (cross country harder again - no natural spring when you sink in a puddle)(Don't know if you remember that the Chinese Olympics has lots of track records broken - the track was more springy than other years). The treadmill alters the running style a bit as well, having a longer stride and leaving the foot longer on the belt but I can't remember what this did.
That's the physical side. The mental side of course is that it can be boring (the worst one I have been on was placed facing a wall - I can run a 10k, maybe a half marathon, race tomorrow no problem, but I was off that one before I ran a mile!). Treadmills are boring and there is no push to keep you going. On a road you can spot things in the distance and think "I'll just run to there" or see a runner to catch up in the distance - more things to concentrate on.
You can repeat a treadmill run anywhere but different weather makes every outside run different, and you can set the exact work out that you want on the treadmill (such as hills, speed, distance and time).
Good points for a treadmill then (better than road running):
- You can repeat the workout exactly week to week
- You can run at any time fo the day or night
- You can run in any weather (for example when the paths are icy)
- Treadmill users tend to go to the gym and so can use other cardiovascular training machines such as cycles, rowers, etc.. and perhaps a pool or sauna to relax in afterwards
- You can set the exact work out that you want - say a 2 mile run or 20 minute run
- The "road" is slightly sprung and easier on your joints
- Treadmill is inside and warm
- You can watch the TV on a treadmill making better use of your time (watch Eastenders and do a half hour run at the same time!)
- You don't have to stop for road junctions
Road running (better than treadmill)
- Its harder on your muscles but gives you a better workout at the same speed
- There is a lot of variety outside - you can vary your route easily
- As you run you can set goals such as running to the next road junction, catching up another runner etc.
- You Have to stop for road junctions and that gives you a quick breather
- You can avoid the TV for half an hour or more
- All races are outside and all social running is outside making outdoor running a more social event
- You see a lot of interesting things running - you go further than you would normally walk but are going slower than you would in a car letting you see more things
- Its a great way to explore an area - try running down every road within a half hour run distance from your house over a few runs
- It stimulates the brain as you go (treadmills can be boring)
- You can run anywhere and only need to buy trainers, Shorts and a T Shirt - no gym or expensive kit
- Cross country runs and hill runs are fun and muddy, wet and cold, but great!!
But at the end of the day, it is a personal choice
When it comes to treadmill and road running and which is easier and better, some people say treadmill, some say roads... personal choices really I am afraid to say. Both have good and bad points. For example I missed 2 weeks road running in the winter - too icy!
Physically treadmill running is easier
I have read a few studies (proper scientific ones measuring oxygen use and things like that) and the results suggest that road running is about 10% harder than a treadmill. To keep the sums easy that means that if you want to have the same effect as a running at 10km/h on the road you need to put the treadmill at 11km/h (see I like easy sums).
There are actually more differences than you would imagine from road running and treadmill running to account for this. One of the big ones is that the treadmill is flat - roads go up and down, the other main one is wind resistance - this counts for a large difference. The treadmill surface is springy and that bounces you back when you land on it (but also reduces the stress on your body) where roads arn't so springy so are harder (cross country harder again - no natural spring when you sink in a puddle)(Don't know if you remember that the Chinese Olympics has lots of track records broken - the track was more springy than other years). The treadmill alters the running style a bit as well, having a longer stride and leaving the foot longer on the belt but I can't remember what this did.
That's the physical side. The mental side of course is that it can be boring (the worst one I have been on was placed facing a wall - I can run a 10k, maybe a half marathon, race tomorrow no problem, but I was off that one before I ran a mile!). Treadmills are boring and there is no push to keep you going. On a road you can spot things in the distance and think "I'll just run to there" or see a runner to catch up in the distance - more things to concentrate on.
You can repeat a treadmill run anywhere but different weather makes every outside run different, and you can set the exact work out that you want on the treadmill (such as hills, speed, distance and time).
Good points for a treadmill then (better than road running):
- You can repeat the workout exactly week to week
- You can run at any time fo the day or night
- You can run in any weather (for example when the paths are icy)
- Treadmill users tend to go to the gym and so can use other cardiovascular training machines such as cycles, rowers, etc.. and perhaps a pool or sauna to relax in afterwards
- You can set the exact work out that you want - say a 2 mile run or 20 minute run
- The "road" is slightly sprung and easier on your joints
- Treadmill is inside and warm
- You can watch the TV on a treadmill making better use of your time (watch Eastenders and do a half hour run at the same time!)
- You don't have to stop for road junctions
Road running (better than treadmill)
- Its harder on your muscles but gives you a better workout at the same speed
- There is a lot of variety outside - you can vary your route easily
- As you run you can set goals such as running to the next road junction, catching up another runner etc.
- You Have to stop for road junctions and that gives you a quick breather
- You can avoid the TV for half an hour or more
- All races are outside and all social running is outside making outdoor running a more social event
- You see a lot of interesting things running - you go further than you would normally walk but are going slower than you would in a car letting you see more things
- Its a great way to explore an area - try running down every road within a half hour run distance from your house over a few runs
- It stimulates the brain as you go (treadmills can be boring)
- You can run anywhere and only need to buy trainers, Shorts and a T Shirt - no gym or expensive kit
- Cross country runs and hill runs are fun and muddy, wet and cold, but great!!
But at the end of the day, it is a personal choice
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