Question

a force of 20 newton acting on a body of mass 10 kg is found to double its velocity in 8 seconds.find the initial velocity.

Answer 1

Force = F = 20N

mass = m = 10kg

initial velocity = u = ?

final velocity = v = ?

Time = t = 8s

v = 2u (given from question)
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F = ma

a = F/m

a = 20N/10kg

a = 2N/kg

a = 2m/s²
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a = (v-u)/t

a = (2u-u)/t

a = u/t

u = at

u = 2m/s²(8s)

u = 10m/s

so initial velocity = u = 10m/s

final velocity = 2u = 2(10m/s) = 20m/s
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