a truck of mass 1500kg travels at a steady speed of 72kmh-1. calculate the force exerted by the engine if the power output if 80kw. i not sure how this works...help?
2007-12-29 01:40:34 · 3 answers · asked by jenille a 2 in Science & Mathematics ➔ Physics
Work is force times distance W=F*D
And Power is work per unit time and therefore P=F*V
In the above question the mass of the truck is irrelevant.
You have to convert the speed to meters/second (1 Km/hr *1000 km/m * 1hr/60min * 1min/60seconds = ___ m/s )
and it will be V.
P= 80 000 watts and then you use th equation P=F*V
2007-12-29 01:50:49 · answer #1 · answered by David Dodeca 5 · 1⤊ 0⤋
Since the truck is moving at a steady speed, I believe the mass of the truck is irrelevant and misleading. The force is wind resistance and probably small amount of friction through the wheels and transmission which can be ignored. (By the way, the truck is using about 107 HP of it's total HP capability.) Use the standard formula:
Power = Force X (Distance / Time )
You can work out the solution in whatever units you would like.
http://apps.caes.uga.edu/sbof/main/lessonPlan/forceSpeedHorsePower.pdf
http://www.statman.info/conversions/power.html
2007-12-29 01:56:47 · answer #2 · answered by Skeptic 7 · 1⤊ 0⤋
Power = Force x Speed
Force = Power/Speed
Force = 80000 watts/(72km/hr)(1000m/1km)(1hr/3600sec)
Force = 4000 Newtons ANS
teddy boy
2007-12-29 01:52:37 · answer #3 · answered by teddy boy 6 · 1⤊ 0⤋