Question

Q.Maximum range of the projectile is 100km.The initial velocity of projectile at the place where g=10 m/s^2 will be:
a)100m/s
b)1000m/s
c)10km/s
d) 100km/hour​

Answer 1

Answer:

c) 10km/s

Given :

Range = 100 km

Value of g = 10 m / sec²

We know if range is maximum :

Ф = 45 .

We have expression of Range :

R = u² sin 2 Ф / g

100 = u² sin 2 × 45 / 10

100 = u² sin 90 / 10

Value of sin 90 = 1

100 = u² / 10

u² = 1000

u = √ 1000

u = 10 √ 10 km / sec