1. How much work does a supermarket checkout attendant do on a can of soup he pu
ID: 1881777 • Letter: 1
Question
1. How much work does a supermarket checkout attendant do on a can of soup he pushes 0.430 m horizontally with a force of 4.80 N? Express your answer in joules and kilocalories.
_________J
_________kcal
2. Suppose a car travels 108 km at a speed of 40.0 m/s, and uses 2.00 gallons of gasoline. Only 30% of the gasoline goes into useful work by the force that keeps the car moving at constant speed despite friction. (The energy content of gasoline is 1.3 108 J per gallon.)
(b) If the required force is directly proportional to speed, how many gallons will be used to drive 108 km at a speed of 28.0 m/s?
_________ gallons
3.(a) Calculate the force needed to bring a 800 kg car to rest from a speed of 85.0 km/h in a distance of 110 m (a fairly typical distance for a nonpanic stop).
_______________N
(b) Suppose instead the car hits a concrete abutment at full speed and is brought to a stop in 2.00 m. Calculate the force exerted on the car and compare it with the force found in part (a), i.e. find the ratio of the force in part(b) to the force in part(a).
______________(force in part (b) / force in part (a))
Explanation / Answer
1) work done = Force * displacement
= F*S
= 4.8*0.43 = 2.064 J
= 2.064 / 4184 = 5*10^-4 Kcal
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.