I don't really have any clue on this problem...(adsbygoogle = window.adsbygoogle || []).push({});

1. The problem statement, all variables and given/known data

A sled with mass 8.00 kg moves in a straight line on a frictionless horizontal surface. At one point in its path, its speed is 4.00 m/s. after it has traveled 2.5m beyond this point its speed is 6.00 m/s. Use the work energy relation to find the force acting on the sled, assuming that this force is constant and that it acts in the direction of the sleds motion.

2. Relevant equations

W = ∆K

3. The attempt at a solution

The only thing i can think of (which isn't the work energy theorem) is Work = 1/2 MV_{f}^{2}-1/2MV_{i}^{2}

W= 1/2*(8kg)*(6m/s)^{2}-1/2(8kg)*(4m/s)^2

W = 80 J

then use Work = FS Cos(Θ)

80J = F*(2.5m)*Cos(180)

-32N = F

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Work Energy Theorem of a sled

**Physics Forums | Science Articles, Homework Help, Discussion**