Tina is looking out a window and throws marble straight downward toward the sidewalk below at a speed of 5.00 m/s and the window is 39.0 meters above the sidewalk. answer the two questions below, using three significant digits. part a: what is the speed of the ball (11) when it hits the ground? number m/s (remember: enter a magnitude.) part b: after 1.90 s, how far down has the marble travelled?

a) 28.1 m/s

b) 27.2 m

Explanation:

a)

Consider the motion of the marble in downward direction taking down direction as positive

v₀ = initial velocity = 5 m/s

v = final velocity as it hits the ground = ?

a = acceleration = 9.8 m/s²

d = vertical height traveled = 39 m

Using the equation

v² = v₀² + 2 a d

v² = 5² + 2 (9.8) (39)

v = 28.1 m/s

b)

t = time of travel = 1.90 s

y = vertical distance traveled

Using the equation

y = v₀ t + (0.5) a t²

y = (5)(1.90) + (0.5) (9.8) (1.90)²

y = 27.2 m

  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