An 800kg car is at the top of mount wellington ( at a height of 1270m). if the car were allowed to roll down the mountain without the use of any brakes, how fast would the car be travelling when it reaches seal level? There is a coefficient of (dynamic) friction of 0.01 between the road and the car on the way down the mountain.
please help me...if u can explain how to do it that'd be a great help..10 points for best answer
thanx
2006-12-16 12:15:10 · 3 answers · asked by bobby19_9 1 in Science & Mathematics ➔ Physics
uhm, assuming no air resistance, you'd probably have to reduce gravity constant g somehow, then compute the speed as if the car was just falling
specifically, assuming g=9.8, time down comes from
t+9.8*t^2/2=1270
and speed after that time will be 9.8t
2006-12-16 12:23:18 · answer #1 · answered by Anonymous · 0⤊ 0⤋
You seem to be missing a piece of information, which is the actual distance travelled. You can calculate the potential energy, which is completely converted to kinetic energy less the amount consumed by friction. If there really isn't any additional information, you could simply use the a reasonable estimate for the slope of the mountain, which would allow you to calculate a normal force to apply against the dynamic friction.
2006-12-16 12:26:20 · answer #2 · answered by arbiter007 6 · 1⤊ 0⤋
The potential energy of the car at the top of the mountain is ‘mgh’
When it reaches the sea level, the energy is full of kinetic energy (= ½ m V*V) if no energy is wasted due to friction etc.
Hence mgh = ½ m V*V.
From this, V = square root of 2gh.
This is the maximum velocity that the car can have at the sea level.
In your problem V (maximum) = (2 x 9.8 x1270) ^0.5 = 157.7 m/s.
With the only information of the coefficient of friction, one can not calculate the energy lost due to friction.
2006-12-16 13:04:26 · answer #3 · answered by Pearlsawme 7 · 1⤊ 0⤋