Question

Two projectiles thrown at 30° and 45° with the horizontal respectively, reach the maximum height in same time. The ratio of their intial velocities is ______.

Options

• 1 : `sqrt2`

• 2 : 1 

• `sqrt2` : 1

• 1 : 2

Answer 1

Two projectiles thrown at 30° and 45° with the horizontal respectively, reach the maximum height in same time. The ratio of their intial velocities is `underlinebb(sqrt2 : 1)`.

Explanation:

t = `("u"sintheta)/g` 

`"t"_1 = (u_1 sin 30^@)/cancel"g" = ("u"_2 sin 45^@)/cancel"g"`

`"u"_1/2 = "u"_2/sqrt2`

`"u"_1/"u"_2 = 2/sqrt2 = (sqrt2)/1`

`sqrt2 : 1`