Styrofoam ball a mass of 150g. Approx. how much air resistance does it encounter when it has reached terminal?

Question

speed of 2 m/s?
1) 1500 N
2) 150 N
3) 15 N
4) 1.5 N
5) 0 N

Answer 1

Terminal velocity is when the air resistance ("drag") is equal to the weight of the object.

I will assume the experiment is being performed on earth.

Mass of styrofoam ball = 150 g or 0.150 kg
Acceleration due to gravity = 9.8 m/sec²

Weight of ball = m*g = 0.150 kg * 9.8 m/sec² = 1.47 N

The closest of the multiple choice answers is 4) 1.5 N

You could have answered this without a calculator by approximating g as 10 m/sec².
0.150 g * 10 m/sec²= 1.50 N

Answer 2

The term "Terminal Velocity" means that the force of the air resistance is equal to the force with which gravity pulls on the object and therefore it won't get any faster.
150g means the force of gravity is 1.5 N so 4) is the answer.