Question

Two graphs of the same projectile motion (in the xy-plane) projected from origin are shown. X-axis is along horizontal direction and y-axis is vertically upwards. Take `g = 10 ms^(-2)`.
,
The projection speed is :
A. `sqrt(37)ms^(-1)`
B. `sqrt(41)ms^(-1)`
C. `sqrt(14)ms^(-1)`
D. `sqrt(40)ms^(-1)`

Answer 1

Correct Answer - B
Time of flight (T) = 1s
`(2u_y)/g = 1s rArr u_y = 5ms^(-1)`
Range (R) = 4m.
`2(u_x)(u_y).g = 4 rArr u_x = 4 ms^(-1)`
`u = sqrt(u_x^2 + u_(y)^(2)) = sqrt (41) ms^(-1)`
`theta = tan^(-1) (u_y/u_x) = tan^(-1) (5/4)`
`H = (u_y^2)/(2g) = (5)^2/20 = 5/4 = 1.25m`.