Question

If an object is released from a height of 100 metres then its velocity will be
g is 10 m/s)
(A) 20√5. ms
(B) 2 km/s
(C)-20√5m/s
(D) -2 km/s​

Answer 1

Answer:

A) 20 root 5 ms

Explaination

• Given - u = 0

v = ?

h = 100

• To find - V

• Solution -

Formula used

V^2 - u^2 = 2gs

V^2 - 0^2 = 2 (10 ) ( 100)

V^2 - 0 = 2 × 10 × 100

V^2 = 2000 + 0

V^2 = 2000

V = root 2000

V = 2 × 2 × 2 × 2× 5 × 5 ×5

= root 2^2 × 2^2 × 5^2 × 5

V = 2 × 2 × 5 root 5

V = 20 root 5 ms

Answer 2

Given :-

• Height at which an object is released (h) = 100m
• Initial velocity (u) = 0
• g = 10m/s

To find :-

• Final velocity (v)

Solution :-

As we know that

➪ v² = u² + 2gh

➪ v² = (0)² + 2 × 10 × 100

➪ v² = 0 + 2000

➪ v² = 2000

➪ v = √2000

➪ v = √2 × 2 × 2 × 2 × 5 × 5 × 5

➪ v = 2 × 2 × 5 × √5

➪ v = 20√5 m/s

Hence,

• Final velocity of object is 20√5m/s

Note :-

• v = u + gt
• h = ut + ½ gt²