CreatorWorship

My grandson was shooting me with a Nerf gun. Having few “bullets”, he had suction cup and round tipped projectiles. The round ones stung a bit. I wondered why. I thought of two reasons and my daughter thought of one. The suction cup-tipped projectiles flex when they strike, reducing the force of impulse by increasing the time of deceleration of the projectile, since Impulse = Force x time. Secondly, the round-tipped projectiles are thicker, and therefore more massive, increasing momentum from a heavier tip, since Momentum = mass x velocity. Thirdly, given the same force of propulsion, the better aerodynamics of the round tip would increase the speed at contact, increasing the momentum and impulse, since mass x velocity = Force x time (Momentum = Impulse). Physics is quite practical and satisfying in explanation. Perhaps some time I will tell you how to prevent a fireplace from smoking up a room.