the mass of vehicle is 2500000 gm the engine of the car exerts force of 750N find acelaration of car. SEE THE POINTS AND ANSWER FAST SPAM WILL BE REPORTED
Answers
ACCELERATIO IS EQUAL TO 3.33 M/S^2
Explanation:
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Image credit: Timely Alex / Flickr.
HOMETECHNOLOGY & THE FUTURETHE PHYSICS OF SPEEDING CARS
The physics of speeding cars
EXPERT REVIEWERS
Professor Neville Fletcher AM FAA FTSE
Professor Neville Fletcher AM FAA FTSE
Emeritus Professor, University of New England
Visiting Fellow, Australian National University and adjunct professor at The University of New South Wales
ESSENTIALS
Speed continues to be one of the major factors contributing to accidents on Australia’s roads
Even a small reduction in speed can greatly reduce the chance or severity of an accident
Improvements in car design, combined with road education campaigns, have resulted in fewer deaths on Australian roads since the 1970s
More than 4100 people are injured in speed-related incidents each year in Australia
A car travelling at 65 km/h is twice as likely to be involved in a crash as a car travelling at 60 kilometres per hour
It may not seem like much, but driving even a few kilometres per hour above the speed limit greatly increases the risk of an accident.
Many of us cheat a little when driving. We figure that while the speed limit is 60 km/h the police won't pull us over if we sit on 65. So we happily let the speedo hover just above the speed limit, unaware that by so doing we are greatly magnifying our chances of crashing.
Using data from actual road crashes, scientists at the University of Adelaide estimated the relative risk of a car becoming involved in a casualty crash—a car crash in which people are killed or hospitalised—for cars travelling at or above 60 km/h. They found that the risk approximately doubled for every 5 km/h above 60 km/h. Thus, a car travelling at 65 km/h was twice as likely to be involved in a casualty crash as one travelling at 60 km/h. For a car travelling at 70 km/h the risk increased fourfold. For speeds below 60 km/h the likelihood of a fatal crash can be expected to be correspondingly reduced.
STOPPING DISTANCE CALCULATOR
Small conditions can make a big difference to the time it takes you to stop your car, such as going a few km/hr slower or being alert on the road.
INTERACTIVEInitial speed
100 km/h
Reaction time
3 sec
Rate of deceleration
14 m/s2
metres travelled before car stops
metres travelled before brakes are fully applied
The physics that drive you
REACTION TIME
One reason for this increased risk is reaction time—the time it takes between a person perceiving a danger and reacting to it. Consider this example. Two cars of equal weight and braking ability are travelling along the same road. Car 1, travelling at 65 km/h, is overtaking Car 2, which is travelling at 60 km/h. A child on a bicycle—let's call him Sam—emerges from a driveway just as the two cars are side-by-side. The drivers both see the child at the same time and both take 1.5 seconds before they fully apply the brakes. In those few moments, Car 1 travels 27.1 metres and to stop than Car 2, a 12 per cent increase.
We can now see why Car 1 is more likely than Car 2 to hit Sam. If Sam is 40 metres from the cars when the drivers see him, Car 2 will stop just in time. Car 1, though, will plough straight into him. By re-writing the first equation, we can calculate the speed at which the collision occurs:
Vf=V20−2ad−−−−−−−−√=8.2 metres per second
(where d = 40 metres minus the reaction distance of 27.1 metres = 12.9 metres).
Thus, the impact occurs at about 30 kilometres/hour, probably fast enough to kill Sam. If the car's initial speed was 70 kilometres/hour, the impact velocity would be 45 kilometre has a longer than average reaction time, then he or she may hit Sam without having applied the brakes at all.
IMPACT ON A PEDESTRIAN
Because the pedestrian, Sam, is so much lighter than the car, he has little effect upon its speed. The car, however, very rapidly increases Sam's speed from zero to the impact speed of the vehicle. The time taken for this is about the time it takes for the car to travel a distance equal to Sam's thickness—about 20 centimetres. The impact speed of Car 1 in our example is about 8.2 metres per second, so the impact lasts only about 0.024 seconds. Sam must be accelerated at a rate of about 320 metres per second per second during this short time. If Sam weighs 50 kilograms, then the force required is the product of his mass and his acceleration—about 16,000 newtons or about 1
Modern cars with low streamlined bonnets are more
KILLER SPEED
All these factors show that the risk of being involved in a casualty crash increases dramatically with increasing speed. In the University of Adelaide study referred to earlier, this was certainly true in zones where the speed limit was 60 kilometres/hour: the risk doubled with every 5 kilometres/hour above the speed limit. A corresponding decrease is to be expected in zones with lower speed limits.
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