Question

A particle is projected from a point (0, 1) on Y-axis (assume + Y direction vertically upwards) alming towards a point (4,9). It falls on ground on x axis in 1 sec. Find speed of projection. Taking g=10m/s^2 and all coordinate in metre.​

Answer 1

tanΦ=9-1/4-0=2=perpendicular/base. ...........(1)

where Φ is angle of projection

given that time of flight is 1 second

from s=ut-1/2gt2

(-1)=usinΦ(1)-1/2(10)(1)2 final displacement is -1 when it hit the ground ok!!

usinΦ=4

then

ucosΦ=usinΦ/tanΦ=4/2=2 (from equestion (1) tanΦ=2 )

then x coordinate = VxT=(2)X(1)=2 (Vx = horizontal componant of velocity)

particle hit the ground at (2,0) OK!!!!!!!!!