Calculating Final Speed and Direction of a Moving Object in a Collision

[vongola13th]

Homework Statement

A force that averages 1200N is applied to a 0.4kg steel ball moving at 14m/s in a collision lasting 27ms. If the force is in a direction
opposite the inital velocity of the ball ,find the final speed and direction of the ball

Homework Equations

n/a

The Attempt at a Solution

I used FdeltaT=mv
1200(27x10^-3)=0.4(v2-v1)
32.4=0.4v2-5.6
38/0.4=v2
95m/s =V2. Is this correct?

 

[rude man]

∫Fdt = Δp is a vector equation.
You have defined the impulse FΔt as positive, so v1 is negative.

 

[vongola13th]

∫Fdt = Δp is a vector equation.
You have defined the impulse FΔt as positive, so v1 is negative.

so it would be 32.4-5.6=26.8
26.8/0.4=67m/s?
Is this right?

 

[rude man]

so it would be 32.4-5.6=26.8
26.8/0.4=67m/s?
Is this right?

Yes it is.