1.

(ii) Two masses 26 kg and 24 kg are attached to the ends of a string which passesover a frictionless pulley. 26 kg is lying over a smooth horizontal table. 24 kg mass is moving vertically downward. Find the tension in the string and the acceleration in the bodies.

Answer»

TOPIC :- Law's of motion

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⏭ First of all make an free BODY diagram "FBD" for the given question [ I've attached the FIGURE refer it ].

POINTS to keep in mind while drawing FBD's :

✏ Assume all the objects to be point particle.

✏ Weight 'mg' acting vertically downward in direction.

✏Keep all the forces tail to tail.

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CALCULATION

\longrightarrow\:\:\sf Acceleration= \dfrac{F_{net}}{M_{total}} \\

\longrightarrow\:\:\sf Acceleration= \dfrac{mg}{M_{total}} \\

\longrightarrow\:\:\sf Acceleration= \dfrac{mg}{m_1 + m_2} \\

\longrightarrow\:\:\sf Acceleration= \dfrac{(24)g}{24 + 26} \\

\longrightarrow\:\:\sf Acceleration= \dfrac{24 \times 10}{24 + 26} \\

\longrightarrow\:\:\sf Acceleration= \dfrac{240}{50} \\

\longrightarrow\:\: \underline{ \boxed{ \sf Acceleration= 4.8 \:  {ms}^{ - 2} }} \\

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✒Now, let's calculate the tension of the string. Refer figure No.2.

✒Here Acceleration (a) is acting vertically downward. So, dominating force will be mg.

✒By using Newton's second law of motion we have :

\longrightarrow\:\:\sf m_1g - T = m_1a \\

\longrightarrow\:\:\sf 24 \times 10 - T = 24 \times 4.8 \\

\longrightarrow\:\:\sf 240 - T = 115.2 \\

\longrightarrow\:\:\sf T = 240 - 115.2 \\

\longrightarrow\:\: \underline{ \boxed{\sf T = 124.8  \: N}}\\

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Here, I've given step by step explaination. You can calculate the tension in the string and Acceleration by given below formula directly :

Tension in the string :-

\dag\:\bf T = \dfrac{m_1m_2}{m_1 + m_2}g

Acceleration :-

\dag\:\bf a = \dfrac{m_1}{m_1 + m_2}g

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