# What is the bullet's initial speed?

A bullet of mass 4.6 g strikes a ballistic pendulum of mass 3.1 kg. The center of mass of the pendulum rises a vertical distance of 6.5 cm. Assuming that the bullet remains embedded in the pendulum, calculate the bullet's initial speed.

### 2 Answers

Relevance

- Anonymous2 months ago
work it backwards

PE came from KE

mgh = ½mv^2

v = √(2gh) = √(2*9.8*0.065) m/sec = 1.13 m/sec

conservation of momentum shall apply

4.6g*V = 3104.6g*1.13m/sec

V = 762 m/s

- Login to reply the answers

- Anonymous2 months ago
PE at the top of the arc = (4.6 g + 3.1 kg) * g * 0.065 m

KE at the bottom of the arc right after the bullet embeds itself is the same, solve for v. KE = 1/2 * mass * speed^2

To calculate the speed of the bullet, use conservation of momentum

speed of bullet * mass of bullet = ((4.6 g + 3.1 kg) * speed from the above step.

- Login to reply the answers

Still have questions? Get your answers by asking now.