A golf ball is thrown down the slope as shown Its initial ve

A golf ball is thrown down the slope as shown. Its initial velocity, u. is perpendicular to the slope. Determine the initial velocity of the golf ball d = 100 m, e = 20 m, theta = 30 degrees.

Solution

Let T be the time taken by the particle. During this time the displacement of the projectile to the plane is zero.

Hence,

u(sin90^o)T- 1/2 g(cos30^o)T²=0

Or, T=  u/0.433 = 2.31u.............................(1)

Range,

R= u(cos90^o)T+1/2 g(sin30^o)T²

Or, 100 = 2.453T² (taking g=9.8 m/s²)

Or, T = 6.38

So, from (1)

u = 14.75 m/s........................Ans