In a Little League baseball game, the 145 g ball enters the strike zone with a speed of 15.0 m/s . The batter hits the ball, and it leaves his bat with a speed of 21.0 m/s in exactly the opposite direction. What is the magnitude of the impulse delivered by the bat to the ball?

5.22 Ns

Explanation:

A consequence of Newton's second law of motion is that:

Impulse = change in momentum

The initial momentum = (0.145 kg) × (15.0 m/s)

The final momentum = (0.145 kg) × (-21.0 m/s)

The final momentum has a negative sign because the ball returned in an opposite direction.

Change in momentum = final momentum - initial momentum = (0.145 kg) × (-21.0 m/s) - (0.145 kg) × (15.0 m/s)

= -0.145(21.0 + 15.0) kg m/s

= -0.145 × 36.0 kg m/s

= -5.22 kg m/s

The magnitude of the impulse is thus 5.22 Ns.

  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

well clustered together.

points close on a scatter diagram