A computational model predicts the speed of a roller coaster car at different heights given its speed at the lowest height of its journey, which is at ground level. The speed at the lowest point is 30 m/s. What is the prediction for its speed when it is at a height of 20 m?(1 point) 18.8 m/s

15.9 m/s

37.5 m/s

22.5 m/

The answers to this test are:

1. What is the maximum speed when the conditions are mass = 450 kg, initial height = 30 m, and the roller coaster car is initially at rest?

24.2 m/s

2. A computational model predicts the maximum height that a roller coaster car can reach when the lowest height of its journey is at ground level, where it has a speed of 20 m/s. Given these conditions, what is the maximum height?

20.4 m

3. A computational model predicts the speed of a roller coaster car at different heights given its speed at the lowest height of its journey, which is at ground level. The speed at the lowest point is 30 m/s. What is the prediction for its speed when it is at a height of 20 m?

22.5 m/s

4. A computational model predicts the maximum potential energy a roller coaster car can have given its mass and its speed at the lowest point of its journey. Its mass is 350 kg, and it speed at a height of 0 m is 25 m/s. What is the prediction for its maximum potential energy?

109,375 J

5. What is the benefit of using simple computational models in a spreadsheet application, like the one used in this course, to predict mechanical energy and related values?

It is easy to calculate new scenarios.

an obstruction

  the grams     of oxygen gas   that can be produced     is 20.6   grams of o₂

calculation

2liclo₃ →   2 licl + 3 o₂

step 1:   find the moles of liclo₃

moles = mass÷ molar mass

from periodic table the molar mass of liclo₃ =6.9 +35.5   +(16 x3) =90.4 g/mol

moles=38.7 g÷90.4 g/mol=0.4281   moles

step 2:   use the   mole ratio   to calculate the moles of o2

from equation above, liclo₃: o₂   is 2: 3  

therefore the moles of   o₂=0.4281 moles x3/2 =0.6422   moles

step 3: find mass   of o₂

mass= moles x molar mass

from periodic table the   molar mass of   o₂ = 16 x2= 32 g/mol

mass=0.6422   moles   x   32 g/mol = 20.6 grams of o₂