Question

1----a particle projected at an angle alpha with the horizontal from the foot of an inclined plane making an angle beta with horizontal.which of the following expression hold good if the particle strikes the incline plane normally?

ans-cos beta=2tan(alpha-beta)

Answer 1

this is your right answer

answer = cos beta = 2tan(alpha - beta)

i hope it's helpful to you

Answer 2

Answer: 2tan(alpha- beta)= cot beta

Explanation: we know that time of flight

t= 2usin$)/g

As g has two components gcosbeta,gsinbeta

Therefore t=2usin(alpha- beta)/gcosbeta

Using the equation v=u+at

V=0, u=ucos(alpha-beta), g=gsinbeta ,T=t

Therefore 0=ucos(alpha-beta)-gsinbeta*2usin(alpha-beta)/gcosbeta

Sinbeta*2usin(alpha-beta)/cosbeta=ucos(alpha-beta)

2sin(alpha-beta)/cos(alpha-beta)=cosbeta/sinbeta

2tan(alpha-beta)=cotbeta