Question

a body start with velocity 20m/s after 2 seconds it comes to rest. find the acceleration aquired by the body.
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Answer 1

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★ Gɪᴠᴇɴ :-

• Initial velocity = 20 m/s
• Comes rest after 2 seconds

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★ Tᴏ Fɪɴᴅ :-

• Acceleration acquired

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★ Sᴏʟᴜᴛɪᴏɴ :-

Finding acceleration acquired using first equation of motion.

v = u + at

Where,

• v → final Velocity = 0 m/s
• a → acceleration = ?
• u → initial velocity = 20 m/s
• t → time taken = 2 s

Note :- Here , the final velocity ( v ) will be zero because the boday comes rest after two second . So , final velocity ( v ) = 0 m/s.

Substituting the values we have,

⇒ 0 = 20 + a(2)

⇒ - 20 = 2a

⇒ a = -20 ÷ 2

⇒ a = - 10 m/s²

Note :- Negative symbol show that the body has retardation.

Hence , acceleration of the body is - 10 m/s²

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Answer 2

Given :-

• Initial Velocity = 20m/s.

• Time = 2 seconds.

• Final Velocity = 0m/s.

To Find :-

• Acceleration Of the Body.

Solution :-

Use The First Equation Of Kinematics,

v = u + at.

Here,

v = Final Velocity,

u = Initial Velocity,

a = Acceleration,

t = Time.

Now, Put the values.

⇒ 0 = 20 + 2a.

⇒ 2a = -20.

⇒ a = -20/2.

⇒ a = -10m/s²

Hence, Acceleration Of The Body = -10m/s².

☆ Here, Negative Sign Shows Retardation.