if mass of an object is decreased to half and acting force is reduced by quarter the acceleration of its motion​

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Explanation:

According to Newtons second law of motion

F = mass * acceleration

F = ma

If mass of an object is decreased to half, then m₂ = 1/2 m

If acting force is reduced by quarter, then F₂ = 3/4 F

F₂ = m₂a₂

3/4F = 1/2m a₂

Divide both expressions

(3/4F)/F = (1/2m)a₂/ma

3/4 = 1/2a₂/a

3/4 = a₂/2a

4a₂ = 6a

2a₂ = 3a

a₂ = 3/2 a

Hence the acceleration of its motion will be one and a half of its original acceleration.

we're given that v₀ = 0 and a = 5.4 m/s². therefore, since v = at + v₀ for constant acceleration the equation for velocity is

after 28s,

m/s

which i would round to 150 m/s as my final answer