Assume: the bullet penetrates into the block

and stops due to its friction with the block.

the compound system of the block plus the

bullet rises to a height of 0.13 m along a

circular arc with a 0.23 m radius.

assume: the entire track is frictionless.

a bullet with a m1 = 30 g mass is fired

horizontally into a block of wood with m2 =

4.2 kg mass.

the acceleration of gravity is 9.8 m/s2 .

calculate the total energy of the composite

system at any time after the collision.

answer in units of j.

taking the same parameter values as those in

part 1, determine the initial velocity of the

bullet.

answer in units of m/s.

To solve this problem we will start considering the total energy of the system, which is given by gravitational potential energy of the total of the masses. So after the collision the system will have an energy equivalent to,

Here,

= mass of bullet

= Mass of Block of wood

The ascended height is 0.13m, so then we will have to

PART A)

PART B) At the same time the speed can be calculated through the concept provided by the conservation of momentum.

Since the mass at the end of the impact becomes only one in the system, and the mass of the block has no initial velocity, the equation can be written as

The final velocity can be calculated through the expression of kinetic energy, so

Using this value at the first equation we have that,

elly's long hair:

a. if the salon only takes cash, then this isn't the problem. it doesn't matter how much she has in her checking account.   she can't get a haircut until she has the cash.

b. if she has overdraft protection, then there's no problem.   she can go ahead and write a check that her account can't cover, then sometime later, pay the bank some outrageous usury for loaning her a few bucks for a few days, but with beautiful hair.

c. if elly has some principles, and doesn't want to write a bad check, then now she has a problem.   her desire for the new hairstyle is in conflict with her honesty and integrity.

d.   if the bank will not process a check she writes, then even if she had a million $$ in her account, she couldn't use any of it.   the amount she has in her account is not the problem.   and if i may suggest, she might as well close her checking account, and put the money where it'll work for her.   it's not doing her a bit of good in a checking account, since she can't write any checks.

justin can't pay the full balance:

a. he can't even handle the credit limit he has now.   under no circumstances should he ask for a higher limit.

b.   he can ask for the grace period to be extended.   but that's no solution, the bank will almost certainly refuse anyway, and there are much better options.   he knew the rules of his credit card when he started using it.

c.   he definitely should pay the interest on the balance, plus as much of the balance as he can cover at the same time.

d.   he definitely should pay the minimum otherwise they could shut down his card.   he should also pay as much more as he possibly can.   he should also remember the awkward situation he's in, stop buying stuff on credit that he can't afford, and avoid adding any more debt.

i'd say that justin's best best option isn't on this list of choices.   what he has to do:   pay as much as he can at least the minimum payment plus as much more as he can and then avoid adding more debt.

what is the speed of a softball that travels 20m in 2secs

speed = 20/2 = 10 m/s