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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
Two bodies of masses 10 kg and 20 kg respectively kept on a smooth, horizontal surface are tied to the ends of a light string. A horizontal force F = 600 N is applied to
(i) A, (ii) B along the direction of string.
What is the tension in the string in each case?

Horizontal force, F = 600 N

Mass of body A, m1 = 10 kg

Mass of body B, m2 = 20 kg

Total mass of the system, m = m1 + m2 = 30 kg

Using Newton’s second law of motion,

                        F = ma 

Acceleration (
a) produced in the system can be calculated as, 

         straight a space equals space straight F over straight m = 600 over 30 space equals space 20 space m divided by s squared space

When force is applied on a body A. 

Equation of motion can be written as, 

F - T = m1a

Therefore,

T = F - m1a

   = 600 - 10 x 20

   = 400 N                                ...  (i)

When Force is applied on a body B, we have 

F - T = m2a

i.e., T = F - m2

Therefore, 

T = 600 - 20 x 20 = 200 N         ... (ii)

From (i) and (ii), we can say that the answer is different in both the cases. 

Therefore, the answer depends on which end of mass, the force is applied.
285 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

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

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