If a girl runs with a speed of 5km/hr a mirror runs with speed of 5kmph her what is the speed of her image.

Speed of mirror 5 kmph
image is made inside the mirror hence,speed of image=speed of mirror that is 5kmph

I think the speed of image inside the mirror will be 10km/h.

ball a of mass m, after sliding from an inclined plane, strikes elastically another ball b of same mass at rest. find the minimum height h so that ball b just completes the circular motion of the surface at

c.(all surfaces are smooth

explanation:

important: the area between a velocity-time graph and the `time' axis gives the displacement of the object. the slope is the same all the way from a to c, so the cyclist's velocity is constant over the entire displacement he travels. in figure 5.1 are examples of the displacement-time graphs you will encounter.