Thread: Kinematics

P and Q are 4m apart at opposite ends of a smooth plane inclined at 30 degree to the horizontal. Initially a particle S of mass m is projected up the plane from P with speed 8m/s and a particle T of mass 2m is released from rest at Q.

Find the distance of the particles from P at the instant when they collide.

Thanks!

Originally Posted by BabyMilo

P and Q are 4m apart at opposite ends of a smooth plane inclined at 30 degree to the horizontal. Initially a particle S of mass m is projected up the plane from P with speed 8m/s and a particle T of mass 2m is released from rest at Q.

Find the distance of the particles from P at the instant when they collide.

Thanks!

magnitude of acceleration a smooth incline is

basic kinematics equation ...



let point P be , and up the incline be the (+) direction.

motion of particle S up the incline ...



motion of particle T down the incline ...



solve the system for , the position relative to point P where the collision occurs.

thanks for the respond.

can i just ask where did the 2.45 come from?

oh i see.

ok thanks!

d) Find the length of the time that elapses from the beginning of the motion until the combined particle reaches P.

for a,b,c I found out:

the distance of the particles from P = 3.3875m

Vs = 5.55ms^-1

Vt = 2.45ms^-1

Vs+t(after collision) =


So for d) i did:


which t=1.13s (3.s.f)

the answer therefore is 1.13+0.5 = 1.63s

but the actual answer is 1.816 s

where have i gone wrong?

thanks for your help!