Question

Can I get the answer please. or any answer you can if possible

1.Calculate how much energyin calories is obtained from a 20g of a roasted peanut snack pack.

2. If you ate the 20g of peanuts from the problem above, how many minutes of Applied Physics lecture will you be able to sit through? the lucture is50 minutse

3. Using equation 4.2 write down how many kilocalories is requires to climb 116 stairs minute. the eqeation from the queiom " calculate the work done by 55 kg person in climbing a flight of stairs 2.5m high

4.What if we climb 232 stairs? How much energyin kilocalories is required per minute?

5. A San Francisco cable car loses its brakes and runs away down a hill 30 meters high. Using the conservation of energy (in this case gravitational potential energy and kinetic energy ) as discussed in class. Determine the speed at the bottom of thie hill if we assume that there is no friction and that the initial speed is zero.

6.If the brakes of the train above only fail partially resulting in the final velocity at the bottom of the hill to be 5m/sec. How muc kinetic energy does the train have at the bottom of the hill?

7.In the case above where the brakes fail only partially meant that there was some friction between the train and the tracks in order to decrease the final speed down the hill. How much energy was lost due to friction? Let the mass of the train be 8000kg.

Answer 1

1, 20 g of roasted peanuts have the following nutrients : 3.6g Carbs ( energy = 4kcal/g), 10.4g Fat (energy = 9 kcal/g), 5g Protein (energy = 4 kcal/g)

therefore, total energy from 20 g of roasted peanuts = (3.6*4)+(10.4*9)+(5*4) = 128

2. For a 68 kg person, 70 calories get burned in one hour while sitting quietly. So hopefully, we will sit through the whole lecture (just an approximation)

You must have got some equations or tables from class but you did not provide that here. So unable to tell exactly. However, the method is same as first two questions

Now , work done in climbing flight of stairs 2.5 m high is = m*g*h = 55*9.8*2.5 = 1348 joules

5 . speed at the bottom of hill, v = sqrt(2gh)

v = sqrt(2*9.8*30)

v = 24.25 m/s

6. K.E = 0.5*M*V² = 0.5*8000*25 = 100000 JOULES

7. energy lost = change in energy.