Which of the following is a correctly written chemical equation that demonstrates the conservation of mass?

If you look at AIF3 and AICI3, the F ion is smaller than a CI ion. that’s why AICI3 will make a covalent bond while AIF3 will make a ionic bond. explanation: AICI3 doesn’t have a complete transfer of electrons between the metal and the non-metal.

4 0

2 years ago

You drop a ball from a height of 2.0 m, and it bounces back to a height of 1.6 m. (a) what fraction of its initial energy is los

sweet [91]

Answer : Part a) Fraction of energy lost : 20 %

Part b) Speed before and after bounce = 6.3 m/s and 5.6 m/s

Part c) Energy is lost as thermal energy .

Part A) Fraction of energy lost during bouncing :

The energy possessed by any object when present at any height is potential energy . The formula of potential energy is given as :

PE = mgh

where PE = potential energy

,m = mass pf object , g = gravitational acceleration and h = height

Given : Initial height , h₁ = 2 m final height , h₂ = 1.6 m

Initial potential energy : m * g* h ₁

Final potential energy = m* g* h₂

Energy lost = Initial PE - Final PE

= ( mgh₁ - mgh2 )

Fraction of energy lost : $\frac{energy lost}{initial energy}=\frac{mgh1 - mgh2}{mgh1}$

Plugging value in above formula and taking " mg " common =>

Fraction of energy lost = $\frac{mg(h1-h2)}{mg (h1)} * 100$

$= \frac{(h1-h2)}{h1} * 100$

$= \frac{(2 - 1.6) }{2} * 100$

Fraction of energy lost = 20%

---------------------------------------------------------------------------------------------------

Part B ) Speed of ball just before and after the bounce.

Speed of ball before the bounce :

The potential energy gets converted to kinetic energy when it fall from height of 2m , so

Potential energy = kinetic energy

mgh₁ = $\frac{1}{2}$ m v²

or v ² = 2gh₁

Given : g = 9.8 m/s² h= 2 m

v² = 2 * 9.8 m/s² * 2 m = 39.2 m²/s²

v = 6.3 m/s

Speed of ball after bounce :

Potential energy = kinetic energy

mgh₂ = $\frac{1}{2}$ m v²

or v² = 2gh₂

= 2 * 9.8 m/s² * 1.6 m = 31.36 m²/s²

v = 5.6 m/s

---------------------------------------------------------------------------------------------

Part C) The energy lost due to friction. When the ball touches the ground , there occur friction force between the surface of ground and ball , due to which energy is lost as thermal energy .

5 0

3 years ago

Read 2 more answers