Energy savers race, brain burner. this question is about solar cars at the chuck norris institute of technology, cnit, in ocala, florida. in one race, a silicon-dioxide crystal powers a car (mass = 120 kg) from rest to a top speed of 10 m/sec in a time of 1.2 sec.
question: for what distance does the solar car accelerate to get to top speed?
a. 6.0 m
b. 150 m
c. 2.0 m
d. 9.8 m
e. 44.1 m
the answer is (a) the movement of the magnet relative to the coil
answer; ////(a)///100kg 1.0m
1) increasing the current flow
2) increasing the number of coils
3) passing an 'iron core' through the coil of the electromagnet
1). use the definition 1 horsepower = 746 watts
100 watts = (100/746) hp = 0.134 horsepower
2). use the definition power = (work done) / (time to do the work)
and the definition work = (force) x (distance moved)
(3,000 n x 5 m) / second
= (3,000 x 5 n-m) / second
= (15,000 joules) / second
= 15,000 watts
3). use the definition power = (work done) / (time to do the work) , and the definition work = (force) x (distance moved) , and the 'customary' definition of 1 horsepower = 550 foot-pounds per second.
let the answer the number of gallons be called ' g ' until we know what it actually is.
weight of water lifted in 1 minute = (g gallons) x (8.34 pounds/gallon)
the distance it's lifted = 30 feet
work done in 1 minute = (force x distance) = (8.34g x 30) foot-pounds
in just a moment, we're going to need this in seconds:
power = (8.34g x 30 foot-pounds/minute) x (1 minute / 60 seconds)
power = (8.34g x 30/60) (foot-pound-minute/minute-sec)
power = 4.17g foot-pound/sec
the power = 1/2 horsepower = 225 foot-pounds / sec
so finally, 225 = 4.17g
divide each side by 4.17, and we have
g = (225/4.17) gallons
g = 53.96 gallons
i really should check this over, but i've had it up to here with gallons, feet, horsepower, and pounds, so i'm not gonna do it. read my lips. it is what it is. i stand or fall by my answer. what could go wrong ? !