Question

32. A stone is released from a balloon that is
descending at a constant speed of 10 m/s.
Neglecting air resistance, after 20 s the speed
of the stone is (g = 9.8 m/s2)
(a) 2160 m/s
(b) 1760 m/s
(c) 206 m/s
(d) 196 m/s​

Answer 1

Given:

• Initial velocity,u = 10 m/s

• Time taken,t = 20 s

• Acceleration due to gravity,g = 9.8 m/s²

To be calculated:

Calculate the final velocity of a stone ?

Formula used:

v = u + gt

Solution:

We have initial velocity, acceleration due to gravity and time taken. So,Final velocity can be calculated by using first equation for freely falling body:

v = u + gt

★ Substituting the values in the above formula,we get

v = 10 + 9.8 × 20

v = 10 + 98/10 × 20

v = 10 + 98 × 2

v = 10 + 196

v = 206 m/s

Thus,the final velocity of a stone is 206 metres per seconds .

Answer 2

✯✯ QUESTION ✯✯

A stone is released from a balloon that is descending at a constant speed of 10 m/s.Neglecting air resistance, after 20 s the speed of the stone is (g = 9.8 m/s2)

(a) 2160 m/s

(b) 1760 m/s

(c) 206 m/s

(d) 196 m/s

━━━━━━━━━━━━━━━━━━━━

✰✰ ANSWER ✰✰

$\implies\tt{Initial\:Velocity(u)=10m/s}$

$\implies\tt{Acceleration(a)=9.8{m/s}^{2}}$

$\implies\tt{Time\:Taken(t)=20s}$

$\implies\tt{Final\:Velocity(v)=?}$

➥Now ,

➥Using 1st Equation of Motion : -

$\implies\tt{\small{\boxed{\bold{\bold{\green{\sf{v=u+at}}}}}}}$

➥Putting Values : -

$\implies\tt{v=10+\dfrac{98}{\cancel{10}}\times{\cancel{20}}}$

$\implies\tt{v=10+98\times{2}}$

$\implies\tt{v=10+196}$

$\purple\longmapsto\:\large\underline{\boxed{\bf\green{v}\orange{=}\pink{206m/s}}}$

➮So , Final Velocity of the stone is 206m/s.

☛Option (c) is correct....