In your new job, you are the technical advisor for the writers of a gangster movie about Bonnie and Clyde. In one scene Bonnie and Clyde are being pursued by a police car. They are 750m from a level railroad crossing travelling at 100 km/hr. A train is 500 meters from the crossing travelling at 130 km/hr. The level crossing is on the state line, and so if they can beat the train, they could evade capture, at least for a while until they become Federal fugitives. They accelerate at a constant rate of 4 m/s2 toward the crossing. The writers want to know if Bonnie and Clyde make it across the crossing before the train.

Explanation:

Velocity of train 130 km /hr

distance of crossing s = 500 m = .5 km

Time taken by train to reach crossing = .5 / 130 = .003846 hr = 13.85 s

Time taken by gangster to reach the crossing = t

initial velocity u = 100km/h = 27.77 m /s

distance of crossing s = 750 m

acceleration a = 4 m /s

s = ut + .5 a t²

750 = 27.77 t + .5 x 4 x t²

2 t² + 27.77 t - 750 = 0

t = - 27.77 ± √(27.77² + 4 x 2 x 750) / 2 x 2

= - 27.77 ±√ ( 771.17 + 6000) / 4

= - 27.77 ±82.28 / 4

= 13.62 s

So this time is less than time taken by train so it will be able to cross the crossing before train arrives .

atomic = no of protons.

mass number-atomic number = neutron number

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explanation:

physics means: "the branch of science concerned with the nature and properties of matter and energy. the subject matter of physics, distinguished from that of chemistry and biology, includes mechanics, heat, light and other radiation, sound, electricity, magnetism, and the structure of atoms."