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Grade 11Mechanics

A speeder in an automobile passes a stationary policeman who is hiding behind a bill board with a motorcycle. After a 2.0 sec delay (reaction time) the policeman accelerates to his maximum speed of 150 km/hr in 12 sec and catches the speeder 1.5 km beyond the billboard. Find the speed of speeder in km/hr

Profile image of aditi sharma
12 Years agoGrade 11
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1 Answer

Profile image of Apoorva Arora
12 Years ago
Since the policemen started 2 seconds after the speeder left and took 12 more seconds to reach there, thus, the speeder has taken 14 seconds to reach the 1.5 km distance from the billboard. Hence, assuming the velocity of the speeder is constant
it is given as speed= distance/time=385.7 km/hr.