Calculating Force on a Falling Body: 5 kg, a = 15 m/s²

[Ockonal]

Homework Statement

With what power we should force the body with mass 5 kg to make it fall down vertically with acceleration 15 m/s²?

a = 15 m/s²
g = 10 m/s²
m = 5 kg;
F - ?

Homework Equations

F = m×a;
F = m×g;

The Attempt at a Solution

F = m × (g + a);
But this is not right.

p.s. The answer is 26 Newtons.

 

[rock.freak667]

The resultant acceleration is 15 m/s^2, which means that

15 = actual acceleration + acceleration due to gravity

You need to compute the actual acceleration.

 

[Ockonal]

As I understand:
15 = x + g;
x = 5 m/s²;
F = m×a;
F = 5×5 = 25;
That's right? Cause answer is 26.

 

[Ockonal]

As I understand:
15 = x + g;
x = 5 m/s²;
F = m×a;
F = 5×5 = 25;
That's right? Cause answer is 26.

 

[rock.freak667]

As I understand:
15 = x + g;
x = 5 m/s²;
F = m×a;
F = 5×5 = 25;
That's right? Cause answer is 26.

Well using g=9.81 will get you an answer closer to 26N.

 

[Ockonal]

Thanks! It solved my problem.