Question: A force of 25N pushes a curling rock from rest 1.0 m across a frictionless surface. Find the FINAL kinetic energy.

attempts:
Well i guess it would be changeinEk
so i tried Wnet=changeinEk
fnet x changeinD = 1/2mvf^2-1/2mvi^2
to fnet x changeinD +1/2mvi^2=1/2mvf^2
Then divided out mass from both sides because it isn't given then cut out vi because it's 0 and isolated vf to get √(2 x fnetxchangeinD=vf
i got vf= 7.07m/s but how am i supposed to find kinetic without mass? No clue about this question, Thanks.

To find the final kinetic energy, you need to calculate the velocity (vf) of the curling rock first using the information given: the force (fnet) and the distance (changeinD). However, you are correct that you also need the mass (m) of the curling rock to calculate the kinetic energy.

If the mass is not given, you won't be able to calculate the final kinetic energy accurately. However, you can still calculate the velocity using the given force and distance. Here's the correct calculation:

1. Start with the equation: fnet x changeinD + 1/2mvi^2 = 1/2mvf^2.

2. Since the initial velocity (vi) is 0, the equation simplifies to: fnet x changeinD = 1/2mvf^2.

3. Divide both sides of the equation by 1/2m: 2fnet x changeinD = vf^2.

4. Take the square root of both sides to solve for vf: √(2 x fnet x changeinD) = vf.

Based on your calculations, you found vf = 7.07 m/s.

While you cannot obtain the exact value for kinetic energy without knowing the mass, you can still determine the ratio between the final kinetic energy and initial kinetic energy (since the initial kinetic energy is 0, as the curling rock starts from rest).

To summarize, you have correctly calculated the final velocity of the curling rock, but you need to know the mass to determine the exact value of its kinetic energy.