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Motion In Straight Line

Question
CBSEENPH11019912
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A car moving along a straight highway with speed of 126 km h–1 is brought to a stop within a distance of 200 m. What is the retardation of the car (assumed uniform), and how long does it take for the car to stop.

Solution
Initial space velocity space of space the space car comma space straight u equals 126 space km divided by hr space equals space 35 space straight m divided by straight s Final space velocity space of space car comma space straight v space equals space 0 space Before space coming space to space rest comma space Distance space covered space by space the space car comma space straight s space equals space 200 space straight m space Let comma space retardation space produced space in space the space car space equals space straight a Now comma space using space the space third space equation space of space motion comma space space space space space straight v squared space minus space straight u squared space equals space 2 as space rightwards double arrow space left parenthesis 0 right parenthesis squared space minus space left parenthesis 35 right parenthesis squared space equals space 2 space cross times space straight a space cross times space 200 rightwards double arrow space straight a space equals space minus 35 cross times 35 over 2 cross times 200 space equals space minus 3.06 space straight m divided by straight s squared space Time space taken space by space the space car space to space stop space is space given space by space the space first space equation space of space motion. space That space is comma space space space space space space space space straight v space equals space straight u space plus space at rightwards double arrow space space space straight t space equals space fraction numerator left parenthesis straight v minus straight u right parenthesis over denominator straight a end fraction space equals space fraction numerator left parenthesis negative 35 right parenthesis over denominator left parenthesis negative 3.06 right parenthesis end fraction space equals space 11.44 space sec

Some More Questions From Motion in Straight Line Chapter

Is absolute rest or absolute motion possible?

What is the most essential thing to study the motion of a body?

Can a body be always at rest in some frame?

Can a body be in motion in the frame associated with the body itself?

When an object in motion can be considered as particle or point object?

Can you think of physical phenomena involving the moon in which moon cannot be treated as particle?

A train is crossing the bridge. Can it be taken as a particle?

Can a train be taken a particle? Give an example in support of your answer.

 A particle is moving along curved line in space. Is the motion one dimensional?

State which of the following are examples of one, two or three dimensional motion: 

(a) A kite flying in the sky.

(b) The earth revolving around the sun. 

(c) A train moving along the equator of the earth in clockwise direction. 

(d) Accelerated motion of a particle in a straight line.

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