Question

Velocity of the body of mass 20 kg changes from 20m/s to 30m/s in 2 sec. Calculate work done by the body.

Answer 1

Answer:

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Explanation:

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Answer 2

Answer:

A force on a body of mass of 3 kg changes its speed from 20 m/s to 45 m/s in 25 seconds. What is the magnitude of force?

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Here to find magnitude of force , we need acceleration and mass of the body as

Force (f) = mass (m) × acceleration (a) ……….[1]

Now,

Mass of body (m) = 3 kg

Initial speed (u) = 20 m/s

Final speed (v) = 45 m/s

Time taken (t) = 25 sec.

To find acceleration of body , use the Newton ‘s first equation of uniform motion -

v = u + at

Put values in this equation ,

45 = 20 + a (25)

25 = a (25)

a = 1 m/s²

Put the values of m and a in equation [1] to get magnitude of force acting on the bo,

f = 3 × 1 = 3 newton

Explanation:

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