Iposted this earlier but got a confusing answer so pls as best as u can asap!
true or false 1. if a 40 kg person is accelerating at 10 m/s2, then the magnitude of the force acting on him or her is 400 n.
(1 point) true false multiple choice 2. how much force is needed to make a 60 kg object accelerate at a rate of 2.0 m/s2? (1 point)
62 n 62 kg 120 n 120 kg 3. what is the acceleration of a 30 kg object when 180 n of force is applied to it? (1 point)
6.0 m/s^2 60 m/s^2 210 m/s^2 5,400 m/s^2 4. which of the following equations shows how you would solve for mass if you knew the force acting on an object and the acceleration of an object?
(1 point) m = f/a m = fa m = a/f m = f − a s need ! dunno what they are talking about! cant guess!
pls ! thanx in advance

Whoa, whoa... settle down there. We'll sort you out.

All of your questions in life can be solved using one simple formula:
F = m*a

In english, this is 
Force = (mass)*(acceleration)

[1] Let's identify the mass. Kg (kilograms) is a mass unit, so we know that
m = 40.
The acceleration is a = 10 m/s^2.

The question is, is the force 400 N? Let's check against the formula:
F = m*a
F = (40 kg)*(10 m/s^2)
F = 400 kg*m/s^2
F = 400 N

Yes. The answer is true.

[2] The mass is m = 60 kg. The acceleration is a = 2.0 m/s^2. The force is 
F = m*a
F = (60 kg)*(2.0 m/s^2)
F = 120 kg*m/s^2
F = 120 N.


[3] The mass is m = 30 kg. The force is 180 N. Ah, this is a little different, now we don't know the acceleration. But the same formula works:
F = m*a
180 N = (30 kg)*a
180 N / 30 kg  = a
6.0 m/s^2 = a

The acceleration is 6.0 m/s^2.

[4] This is a hypothetical question. Suppose we know the force F and the acceleration a, but we don't know the mass m. I'll put m in a box [m] so that we remember that this is the one we don't know. The same formula works:
F = m*a
F = [m]*a   <--- m is the one we don't know
F / a = [m]

In reality, we would have numbers for F and a, but since we are just pretending we are done!

m = F/a is the formula.

See? Not too bad. :)