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Class 11
Physics
Laws of Motion
a constant retarding force of 50 n is applied to a...

Question:
A constant retarding force of 50 N is applied to a body of mass 20 kg moving initially with a speed of 15 ms^–1. How long does the body take to stop?

Answer:

Retarding force, F = -50 N

Mass of the body, m= 20 kg

Initial velocity of the body, u= 15 m/s

Final velocity of the body, v= 0

UsingNewton's second law of motion, the acceleration (a) produced in the body can be calculated as:

F= ma

-50 = 20 × a

∴ a = -50 / 20 = -2.5 m/s²

Usingthe first equation of motion, the time (t) taken by the body to come to rest can be calculated as:

v= u + at

∴ t = -u /a = -15 / -2.5 = 6s

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Question:
A constant retarding force of 50 N is applied to a body of mass 20 kg moving initially with a speed of 15 ms^–1. How long does the body take to stop?

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Question: A constant retarding force of 50 N is applied to a body of mass 20 kg moving initially with a speed of 15 ms–1. How long does the body take to stop?

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Question:
A constant retarding force of 50 N is applied to a body of mass 20 kg moving initially with a speed of 15 ms^–1. How long does the body take to stop?