Question

A boy is whirling a stone tied with a string in a horizontal circular path as shown in a followig figure . if the string breaks ,then the stone ?​

Answer 1

Explanation:

A church is 600 m due west of a flagpole. A statue is on a bearing of 160° from the church and on a bearing of 220° from the flagpole.

To find : The distance of the church from the statue.

solution : see diagram, here we put church at point C , statue at point B and flagpole at A on a line X which is parallel to Y.

from diagram, it is clear that ∠ACB = ∠ABC = 20°

so distance between flagpole and statue is 600m.

now distance between church and statue i.e., CB

here using formula,

cos140° = {AB² + AC² - BC²}/2AB AC

⇒2AB AC cos140° = AB² + AC² - BC²

⇒BC = √{AB² + AC² - 2AB AC cos140°}

= √{600² + 600² - 2 × 600² × cos140°}

= 1128 m

Therefore the distance between church and statue is 1128 m

we have to identify which one of the given reactions , a salt is reacting with a base

a) NaOH + HCl → NaCl + H₂O

b) Cu(OH)₂ + H₂SO₄ → CuSO₄ + 2H₂O

c) KOH + HCl → KCl + H₂O

d) 6NH₄OH + Al(SO₄)₃ → 2Al(OH)₃ + 3(NH₄)₂SO₄

solution : concept : general formula of a base is YOH, where Y is metal and OH is hydroxide ion.

so, NaOH , KOH and NH₄OH, Cu(OH)₂ are base.

HCl , H₂SO₄ are acid.

now let's see the reaction.

a. NaOH (base) + HCl (acid) ⇒NaCl (salt) + water

b. Cu(OH)₂ (base) + H₂SO₄ (acid) ⇒ CuSO₄ (salt) + water

c. KOH (base) + HCl (acid) ⇒ KCl (salt) + water

d. NH₄OH (base ) + Al(SO₄)₃ (salt) ⇒2Al(OH)₃ (base) + 3(NH₄)₂SO₄ (salt)

Therefore option (d) is the reaction of a salt with a base.

Answer 2

Explanation:

When the boy is whirling a stone tied with a string in a circular path, the centripetal force acts towards the center of the circular path. However, when the string breaks the centripetal force ceases and there is no force acting. Thus, the stone as per Newtons first law will continue in a straight line and fly off along the tangent to the circular path.