Question

A force of 500 dynes acts on a mass of 0.5kg over a distance of 20m . Assuming
that the mass is initially at rest, find the final velocity and time
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Answer 1

Explanation:

500 dyne : 0.005 N

Now from F = ma

we get a = F/m

= 0.005/0.5

= 0.01 m/s2

now u= 0

then v2 = u2 +2as

so v2 = 0 + 2×0.01×20

v2 = 0.4

v : 0.632 m/s

Answer 2

Answer:

V= 200 cms

t=20s

Explanation:F=500 dynes=500 gcms-^2

m=0.05 kg = 50 g

a=F/m=500gcms-^2/50g =10cms-^2

S=20m = 2000 cm

v^2-u^2=2as

v^2-(0)^2=2×10 cms^2 × 2000cm

v^2 = 40000 cm^2s-^2

so, v=200 cms-

v =u +at

200 cms- =0+10cms- ^2 ×t

t = 20 s