a gazelle attempts to leap a 1.8 meter fence. assuming a 45 degree takeoff angle, what's the minimum speed for the jump?

Answer 1

recall that for a projectile motion, the maximum height that the object can reach is given by the formula,
h,max = [(vo)^2 * sin^2 (θ)]/(2g)
where
vo = initial velocity
θ = angle of release
g = acceleration due to gravity = 9.8 m/s^2
the unknown in the problem is vo. thus we just substitute the given in the formula:
h,max = [(vo)^2 * sin^2 (θ)]/(2g)
1.8 = [(vo)^2 * sin^2 (45)]/(2*9.8)
1.8*2*9.8 = (vo)^2 * (1/2)
34.2 = (vo)^2 * (1/2)
70.56 = (vo)^2
vo = sqrt(70.56)
vo = 8.4 m/s

hope this helps~ :)