A playground is surrounded by a fence 2.0 m high. A boy who plays in the
playground kicks a ball vertically upward from a height of 0.2 m with a speed of
10 m/s. How much time does the ball spend above the height of the fence?

Question

A playground is surrounded by a fence 2.0 m high.  A boy who plays in the 
playground kicks a ball vertically upward from a height of 0.2 m with a speed of 
10 m/s. How much time does the ball spend above the height of the fence?

anonymous · Answer

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find u' and then use t=v-u'/g
v=0 at top most point
so find time taken to go maximum that multiplied by 2 gives time above the fence
FIRST FIND u'