Question

Karissa is conducting an experiment on the amount of salt that dissolves in water at different temperatures. She repeats her tests several times using the same procedure.
What can Karissa do to further increase confidence in the results of her experiment?

1.have another scientist run the same exact procedure in her lab

2.include several other liquids for comparison

3.calculate the average amount of salt that dissolves to summarize findings

4.make sure the experiment follows a specific procedure that allows other scientists to produce the same findings

Answer 1

Valid Expressions are; t = ∛(d²/va), a = d/t², a = √(vd/t³), v = at

while the Invalid expressions are;  v = a/t and  d = at

Explanation:

Given expressions

1) v = a/t

2) t = ∛(d²/va)

3) d = at

4) a = d/t²

5) a = √(vd/t³)

6) v = at

First we get our units of parameters

V = m/s, t = sec, d = m, a = m/s²

so

1)

v = a/t

we substitute in our units of parameters

v = m/s² / s = m/s² × 1/s = m/s³

v ≠ m/s³

therefore it is false

2)

t = ∛(d²/va)

we substitute

t = ∛(m² / m/s × m/s²)

t = ∛(m² / m²/s³)

t = ∛(s³)

t = s

correct, the expression is true

3)

d = at

we substitute

d = m/s² × s

d = m/s² × s/1 =  ms/s² = m/s

d ≠ m/s (because d = m)

so expression is false

4)

a = d/t²

we substitute

a = m / s² = m/s²

correct

the expression is true

5)

a = √(vd/t³)

we substitute

a = √(m/s×m / s³) = √(m²/s / s³) = √(m²/s × 1/s³)  = √(m²/s⁴) = m/s²

so a = m/s²

correct

the expression is true

6)

v = at

we substitute in the units

v = m/s² × s = m/s² ×s/1 = ms/s² = m/s

v = m/s

correct

the expression is correctValid Expressions are; t = ∛(d²/va), a = d/t², a = √(vd/t³), v = at

while the Invalid expressions are;  v = a/t and  d = at

Explanation:

Given expressions

1) v = a/t

2) t = ∛(d²/va)

3) d = at

4) a = d/t²

5) a = √(vd/t³)

6) v = at

First we get our units of parameters

V = m/s, t = sec, d = m, a = m/s²

so

1)

v = a/t

we substitute in our units of parameters

v = m/s² / s = m/s² × 1/s = m/s³

v ≠ m/s³

therefore it is false

2)

t = ∛(d²/va)

we substitute

t = ∛(m² / m/s × m/s²)

t = ∛(m² / m²/s³)

t = ∛(s³)

t = s

correct, the expression is true

3)

d = at

we substitute

d = m/s² × s

d = m/s² × s/1 =  ms/s² = m/s

d ≠ m/s (because d = m)

so expression is false

4)

a = d/t²

we substitute

a = m / s² = m/s²

correct

the expression is true

5)

a = √(vd/t³)

we substitute

a = √(m/s×m / s³) = √(m²/s / s³) = √(m²/s × 1/s³)  = √(m²/s⁴) = m/s²

so a = m/s²

correct

the expression is true

6)

v = at

we substitute in the units

v = m/s² × s = m/s² ×s/1 = ms/s² = m/s

v = m/s

correct

the expression is correct