# Calculating force from distance traveled and initial speed of projectile

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1. Oct 20, 2014

### Felchi

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

Estimate the average force exerted by a shot-putter on a 7.0-kg shot if the shot is moved through a distance of 3.0m and is released with a speed of 10m/s .
2. Relevant equations
F=ma
Maybe the Five Equations for constant acceleration?

3. The attempt at a solution
So my guess is that I need to find acceleration. I tried:

0^2=10m/s^2+2(a)3m
0=100 m^2/s^2+6m(a)
(-100 m^2/s^2)/6m=a
16.67m/s^2=a

So
F=7kg*16.67m/s^2
F=116.67

But I was told this is wrong

2. Oct 20, 2014

### Staff: Mentor

The key to this question, I believe, is the phrase "average force," which is the change in momentum divided by the elapsed time.
$$\bar{F} = \frac{m(v_f - v_i)}{\Delta t}$$