Question

Q) A projectile is thrown in the upward
upward direction
making
angle of 60° with the horizontal direction with
a velocity of 147 m/s. Then the time after which its
inclination with the horizontal is 45° is?
​

Answer 1

Answer:

time = 5.5 s

Explanation:

velocity of the projectile (u) =147 m/s

angle of projection (α)    = 60∘

let the time taken for projectile be t and final velocity be v , where direction is  β = 45 degree

During projectile, the horizontal component remains constant

therefore,  vcos45∘=ucos60∘

                                          = u x 1/√2  = 147 x 1/√2 = 147 /√2 m/s

for vertical motion,,

     vsin45∘      =45sin60∘−9.8t

 147/√2 x 1/√2 = 147 x √3/2 - 9.8t

          9.8t        =  147 x √3/2 - 147/√2 x 1/√2

                        = 147 x √3/2 - 147/2

                        = 147/2 ( √3 - 1)

           9.8t       = 53.8057

                t       = 53.8057 / 9.8

                        = 5.49

                        ~ 5.5 s