Projectile Launch Speed: Solve 876j Work Homework

[Chica1975]

Homework Statement

A projectile launcher did 876j of work on a .398kg projectile what is the launch speed of the projectile?

Homework Equations

W = f*d
mg = 3.9004
after that I am stuck

The Attempt at a Solution

I drew a diagram and tried a few things but am completely stuck. please help.

 

[rock.freak667]

The Attempt at a Solution

I drew a diagram and tried a few things but am completely stuck. please help.

The work done is entirely kinetic

 

[Chica1975]

thanks I will look it up and try again.

 

[fuzzywolf]

W = F * d is only a mathematical tool to calculate how much work is done. The applicable statement of physics is W = $$\Delta$$E

 

[rwisz]

I would approach this problem by using the work-energy theorem, which states that the work done on an object is equal to its change in kinetic energy. In this case, the projectile launcher did 876j of work on the projectile, so we can set up the following equation:

W = ΔKE

Where W is the work done (876j) and ΔKE is the change in kinetic energy. We can also use the equation for kinetic energy:

KE = 1/2 * m * v^2

Where m is the mass of the projectile (0.398kg) and v is the launch speed we are trying to find. Substituting this into our first equation, we get:

876j = 1/2 * 0.398kg * v^2

Solving for v, we get:

v = √(2*876j/0.398kg) = 74.8 m/s

Therefore, the launch speed of the projectile is 74.8 m/s.