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Motion In Straight Line

Question
CBSEENPH11020683
Wired Faculty App

A ball is dropped from  a high-rise platform at t=0 starting from rest. After 6s another ball is thrown downwards from the same platform with a speed v. The two balls meet at t= 18s. What is the value of v? (take g= 10 ms-2)

  • 74 ms-2

  • 55 ms-1

  • 40 ms-1

  • 60 ms-1

Solution

A.

74 ms-2

For space first space ball space comma space straight u space equals space 0 therefore comma straight s subscript 1 space equals space 1 half space gt subscript 1 superscript 2 space equals space 1 half space straight x space straight g space left parenthesis 18 right parenthesis squared For space second space ball comma space initial space velocity space equals space straight v therefore comma space straight s subscript 2 space equals space vt subscript 2 space plus space 1 half space gt squared straight t subscript 2 space equals space 18 minus 6 space equals space 12 space straight s straight s subscript 2 space equals space straight v space straight x space 12 space plus space 1 half straight g space left parenthesis 12 right parenthesis squared Here comma space space straight s subscript 1 space equals space straight s subscript 2 1 half straight g left parenthesis 18 right parenthesis squared space equals space 12 space straight v space plus space 1 half space left parenthesis straight g right parenthesis space left parenthesis 12 right parenthesis squared straight v equals space 74 space ms to the power of negative 1 end exponent

Some More Questions From Motion in Straight Line Chapter

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.

Define distance.

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