How do you find the force needed to accelerate a 0.007 kg pellet from rest to 125 m/s over a distance of 0.8 m along the barrel?

2 Answers
Mar 24, 2018

Answer:

The force is #=68.36N#

Explanation:

Apply the equation of motion

#v^2=u^2+2as#

The initial velocity is #u=0ms^-1#

The final velocity is #v=125ms^-1#

The distance is #s=0.8m#

The acceleration is

#a=(v^2-u^2)/(2s)=(125^2)/(2*0.8)=9765.625ms^-2#

The mass of the pellet is #=0.007kg#

According to Newton's Second Law of Motion

#F=ma#

The force is #F=0.007*9765.625=68.36N#

Mar 24, 2018

Answer:

#F= 68.36 N#

Explanation:

#m=0.007# #Kg#
#u=0# #ms^-1#
#v=125# #ms^-1#
#s=0.8 m#

Applying a motion equation:

#v^2=u^2 + 2as#
#15 625 = 1.6a#
#a= 9765.625# #ms^-2#

Applying Newton's second law:

#F = ma#
#F=0.007 * 9765.625#
#F= 68.36 N#

Again, that's valid assuming we have no other forces on the motion axis acted on the object whatsoever.