Question

what is acceleration of 1.4 kg object if gravitational force pulls downward on it but air resistance pushes upward with force of 2.5 Newton..is the answer 11.5 m/s square downward or 8 m /s square downward.... please help

Answer 1

we know that when any force act opposing another force its value would decrease so it would be 8

Answer 2

Answer: $8.0 m/s^2$

The gravitational force pulls the object downwards.

Force due to gravity = mass × acceleration due to gravity = mg

$F=1.4 kg \times 9.8 m/s^2=13.72 N$ downward

Air resistance pushes the object upwards.

Air resistance = 2.5 N upwards

Net force in the downward direction = 13.72 N - 2.5 N  = 11.2 N downwards

Acceleration = Force /mass , $a = \frac{11.22 N}{1.4 kg}= 8.0 m/s^2$

hence, the acceleration is $8.0 m/s^2$