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Title: How to calculate average accelaration and force when given mass and velocity? Post by: rjblayz on Nov 15, 2012 A bullet of mass 15g travelling with a velocity of 150m/s strikes a tree and penetrates a distance of 250mm into the timber before coming to rest. What was the average acceleration of the buleet and what was the average force causing the accleration?
I really appreciate any help!!! Title: How to calculate average accelaration and force when given mass and velocity? Post by: nwobie on Nov 15, 2012 use (work done by the force=kinetic energy)
v0^2=2*a*s=2*F/m*s then a=v0^2/(2*s)=4.5*10^(4) m/s^2 <----------- F=m*a=675 N <----------------- ps- all moduli, of course.. but it's simple to understand.. not so simple...!!!! Title: How to calculate average accelaration and force when given mass and velocity? Post by: rjlene on Nov 15, 2012 u^2+2as = v^2
where u = the initial velocity of the bullet. a = the acceleration(actually deceleration) of the bullet. s = the distance that the bullet travels in the timber. v = the final velocity of the bullet. i.e., 150^2+2a*(250/1000)=0^2 22500+0.25*2*a = 0 22500+0.5a = 0 0.5a = -22500 a = -45000 The average acceleration(deceleration) of the bullet was 45000ms^(-2). So, F = ma = [(15/1000)*(-45000)]N = 675N in the opposite direction that the bullet was travelling. The average force that was causing the acceleration(deceleration) was 675N in the opposite direction that the bullet was travelling. |