# Physics... Help!

posted by .

A bullet of mass m=0.060 kg hits a 5.0 kg block with an initial speed of 225 m/s. The block is connected to a spring that is attached to a wall. The friction between the block and the table is negligible. Upon impact, the bullet bounces back from the box with a speed of 75 m/s.
A) Calculate the speed of the block right after the collision.

I thought the equation to use was mv of bullet = (M+m)V of block. I came up with 2.67 but the answer is supposed to be 3.6 m/s.

B) As a result of the collision, the spring compresses to a mazimum of 0.20m. Find the spring constant
--The equation to this is 1/2mv^2 = 1/2kx^2 right? I can't get the answer to this question without the answer to part A.
C) Find the inelastic energy loss during the collision

## Similar Questions

1. ### Physics

A 2.50g bullet, traveling at a speed of 425m/s, strikes the wooden block of a ballistic pendulum. The block has a mass of 270g (a) find the speed of the bullet/block combination immediately after the collision (b) how high does the …
2. ### physics

A heavy wooden block rests on a flat table and a high-speed bullet is fired horizontally into the block, the bullet stopping in it. How far will the block slide before coming to a stop?
3. ### physics

A block of mass M connected to an untstretched horizontal spring of spring constant k is hit by a bullet of mass m which has a velocity V just before the collision. The bullet stays in the block. The coefficient of friction between …
4. ### physics

A 20 g bullet moving horizontally with a speed v hits a 2-kg block of wood resting on a table. After hitting the block the bullet is embedded in the block of wood and the block and the bullet moves a distance of 40 cm before it stops. …
5. ### Physics HELP!

A 20.0 g bullet is fired horizontally into a 85 g wooden block that is initially at rest on a frictionless horizontal surface and connected to a spring having spring constant 156 N/m. The bullet becomes embedded in the block. The bullet …

A 20.0 g bullet is fired horizontally into a 85 g wooden block that is initially at rest on a frictionless horizontal surface and connected to a spring having spring constant 156 N/m. The bullet becomes embedded in the block. The bullet …
7. ### Physics

A bullet of mass m=0.060 kg hits a 5.0 kg block with an initial speed of 225 m/s. The block is connected to a spring that is attached to a wall. The friction between the block and the table is negligible. Upon impact, the bullet bounces …