The reflecting surface of a plane mirror is vertical. A particle is projected in a vertical plane which is also perpendicular to plane of the mirror . The initial velocity of the particle is 10m/s and the angle of projection is 60 degree.The point of projection is at a distance 5m from the mirror .The particle moves towards the mirror .Just before the particle touches the mirror the velocity of approach of the particle and its image is
a)10m/s
b)5m/s
c)103 m/s
d)53 m/s
Acceleration
velocity at time
Power delivered at time t
= F. v
= ma .v
any instant only the component of velocity perpendicular to the mirror matters as parrallel component will be same for both image and object . the perpendicular component is constant= ucos60=5m/s
so the object and image are moving towards each other at a speed of 5m/s
the velocity of approach=10m/s
2)A body of mass m accelerates uniformly from rest to in time The instantaneous power delivered to the body as a function of time t is
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