Question

47.
A stone is projected vertically upwards and rises to a maximum height of 5m The
velocity with which the body was thrown upwards is (take g = 10 m/s)
(A) 5m/s
(B) 10 m/s
(C) 15 m/s (D) 20 m/s
FILTJEE WORLD SCHOOL​

Answer 1

Answer:

(b) Initial velocity of Stone = 10 m/s

Step by step explanations :

given that,

A stone is projected vertically upwards and rises to a maximum height of 5m

here,

we have,

final velocity of the stone = 0 m/s [stone will at rest at the maximum height]

maximum height attained by the stone = 50 m

let the initial velocity at which the stone was thrown be u

by the equation of motion,

v² = u² + 2gh

where,

g = gravitational acceleration

h = maximum height

now we have,

initial velocity(u) = u

final velocity(v) = 0 m/s

height(h) = 5 m

gravitational acceleration(g) = -10 m/s²

putting the values,

(0)² = u² + 2(-10)(5)

u² - 100 = 0

u² = 100

u = √100

u = 10 m/s

so,

velocity of the stone at which it was thrown will be

10 m/s

Answer 2

Answer:

correct option

(B) 10 m/s

Step by step explanations :

given,

final velocity of stone(u) = 0 m/s

maximum height attained by stone(h) = 50m

let the velocity of stone if throwing be u

so,

initial velocity = u

given gravitational acceleration(a) = 10m/s²

v² = u² + 2gh

(0)² = u² + 2(-10)(5)

u² +(-100) = 0

u² - 100 = 0

u² = 100

u = √100

u = 10 m/s

so,

Initial velocity of the stone

= 10 m/s

correct option

(B) 10 m/s