Momentum and energy Definition and 161 Threads

I read the answer of it, but I don't get why the answer is that. And the answer is 1/2 M gun x (M bullet * V bullet / M gun)^2 - 1/2 M gun+you x (M bullet * V bullet/ M gun+you) ^2thx!

https://www.physicsforums.com/attachment.php?attachmentid=3184&stc=1SPEED SPEED OF WAGON1 =10 SPEED OF WAGON2=0 THE SAME WAGONS IMPACTED ELASTIC, AFTER THE COLLISION A LOCK CONJOINT THEM. ALL THE MOLECULES OF THE WAGONS HAVE SPEED 5(AFTER COLLISION-..).WE SIGNIFY A LOSS OF ENERGY SAYING THAT...

Conservation of momentum and energy :D :frown: Wats this question on bout? 1. [HRW6 10.P.026.] In Fig. 10-32a, a 4.00 g bullet is fired horizontally at two blocks at rest on a frictionless tabletop. The bullet passes through the first block, with mass 1.20 kg, and embeds itself in the...

a baskeball and a tennis ball are dropped from the same height simultaneously. The potential energy (PE) is mgh. m=mass(kg) g=9.8m/s/s h=height(m) after the ball hits the floor, the tennis ball flies off as the basket ball bounces. The inital velocity of the basketball after it bounces is...

I'm going on 10 years since I got my (physics) degree, but I haven't done much work besides conceptual stuff in that time and it shows. :mad: Anyway, I decided to crack open my Modern Physics book from school and start working my way through it. The first few problems were OK, but I just...

if you have a spinning body, and then its shape changes so that the moment of inertia changes, what happens? If angular velocity is conserved, since there's no net torque, then it spins a different speed, but the same direction. But then has the rotational kinetic energy changed? And if so...

This one is giving me fits for some reason: A proton of mass m undergoes a head-on collision with a stationary carbon nucleus of mass 12m. The speed of the proton is 300 m/s. Find the velocity of the proton after the collision. Ok, I know that both momentum and energy are conserved. So...

Should be fairly simple, but I'm not so great with physics. Here's a few I'm having trouble with... 1. Under what circumstances (if any) is no work done on a moving object even though a net force acts upon it? 2. What happens to the momentum of a car when it stops? 3. When the...

A 30g bullet is fired horizontally into a 12kg block which is suspended on a long cord. What speed of bullet would cause the center of gravity of the block to rise 8cm? energy approach change of kinetic energy for bullet = change of potential for bullet and block \frac{1}{2}mv^2 = mgh...

We are doing Cons. of Momentum in my intro to physics class.. and I am stuck on this problem: An explosion breaks an object into two pieces, one of which has 1.58 times the mass of the other. If 7370 J were released in the explosion, how much kinetic energy did the heavier piece acquire...

Here's the Problem: A bullet of mass m=19.8 g is shot vertically upward into a block of wood of mass M=119 g that is initially at rest on a thin sheet of paper. The bullet passes through the block, which rises to a height of H=0.71m above its initial position before falling back down. The bullet...