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Laws of Motion

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Physics Part I

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Physics

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Class 10 Class 12

Three masses are placed on the x- axis: 300g at origin, 500g at x = 40 cm and 400 g at x = 70 cm. The distance of the centre of mass from the origin is 

  • 40 cm

  • 45 cm

  • 50 cm

  • 30 cm


A.

40 cm

straight x subscript cm space equals fraction numerator straight m subscript 1 straight x subscript 1 space plus straight m subscript 2 straight x subscript 2 space plus straight m subscript 3 straight x subscript 3 over denominator straight m subscript 1 plus straight m subscript 2 plus straight m subscript 3 end fraction
space equals space fraction numerator 300 space left parenthesis 0 right parenthesis space plus 500 space left parenthesis 40 right parenthesis space plus 400 space left parenthesis 70 right parenthesis over denominator 300 plus 500 plus 400 end fraction
equals space fraction numerator 20000 plus 28000 over denominator 1200 end fraction
space equals 48000 over 1200 space equals 40 space cm
straight x subscript cm space equals fraction numerator straight m subscript 1 straight x subscript 1 space plus straight m subscript 2 straight x subscript 2 space plus straight m subscript 3 straight x subscript 3 over denominator straight m subscript 1 plus straight m subscript 2 plus straight m subscript 3 end fraction
space equals space fraction numerator 300 space left parenthesis 0 right parenthesis space plus 500 space left parenthesis 40 right parenthesis space plus 400 space left parenthesis 70 right parenthesis over denominator 300 plus 500 plus 400 end fraction
equals space fraction numerator 20000 plus 28000 over denominator 1200 end fraction
space equals 48000 over 1200 space equals 40 space cm
1249 Views

Define inertia.

The property by virtue of which the body cannot change its state of rest or uniform motion in a straight line, unless an external force is acting on the body is called as Inertia. 
1316 Views

What is Aristotle’s law of motion?

Aristotle’s law of motion states that an external force is required to keep the body in motion.
2445 Views

State Galileo’s law of motion.

Galileo’s law of motion states that, a body continues to move in the same direction with constant speed, if no force is acting on the body. 
1332 Views

Is Aristotle’s law of motion now correct?

No. Aristotl'e law of motion is false. 
1233 Views

When the branches of an apple tree are shaken, the apples fall down. Why?

The apple fall from an apple tree when it shaken because of inertia of rest. Apple is in a state of rest and when the tree is suddenly shaken, apples still tends to remain in it's same state of rest whereas branches move. 

So, the apples fall down. 
1475 Views