Physics question on mechanics

Question

A force F applied to a mass ml produces an acceleration of 3.0 m/s2. The same

force applied to a second object of mass m2 produces an acceleration of 1.0 m/s2.

(a) Find the value of the ratio ml / m2. (b) If ml and m2 are combined, what will

be the acceleration of the combined mass (ml m2) under the action of the force

F?

can someone please help me with this question.......the only value im given is acceleration, no mass or force...so how do i solve this question...

I drew a free body diagram, the forces acting on the boxes are gravity (9.8) mg but i dont know how i can use that information to solve this question

please help!!!!!!!!!

Answer 1

F= m1*3

F= m2*1

a.

m2*1 = m1*3

so: m1/m2 = 1/3

b.

F=(m1+m2)*a  

but: m1=(1/3)*m2

substituting:

F=((1/3)*m2 + m2)*a

but: F= m2*1

substituting:

m2*1=((1/3)*m2 + m2)a

dividing both sides by m2 a we have:1=((1/3)+1)*a

so a=3/4 m/s2

Answer 2

Using Newton's 2nd Law of Motion,

F = ma

where

F = force applied

m = mass of the body

a = acceleration

For the first mass, m1

F = m1(a) = m1(3) = 3(m1) --- Equation 1

and for the second mass, m2

F = m2(a) = m2(1) = m2

F = m2 --- Equation 2

Since F is constant, Equation 1 = Equation 2, hence

3(m1) = m2

(m1/m2) = 1/3

**************************************...

To calculate the acceleration of the combined masses subjected to the same force, F,

F = (m1 + m2)a

Solving for "a",

a = F/(m1 + m2)

From Equation 1, since F = 3(m1) and m2 = 3(m1), the above equation for "a" is modified to

a = 3(m1)/(m1 + 3m1)

and since m1 appears in the numerator and the denominator, then it will simply cancel out. Therefore, the above equation simplifies to

a = 3/(1 + 3) = 3/4

a = 3/4 m/sec^2

Hope this helps.

Answer 3

Since F = m * a & and you know that you are applyin the same force to each mass, set them equal to each other.

m1 * 3 = m2 * 1  (eliminate the 1 m/s2)

m1 * 3 = m2

There is your RATIO 3:1

Let me think about the other one....  

Answer 4

a force f

ratio ml/s k

just kidding, I couldn't help it....hope you laughed