## Posts tagged Physics Homework Study Help

# Answered: Is momentum always conserve...

It depends on how you define your system. If you include the external object which exerted the external force in a grander system, then the momentum of that system would be conserved. — that is if you define the whole universe as your system, then all the momentum of all matters inside the universe would sum to a constant and be co [...]

# Is momentum always conserved? Even if...

I understand that there are two situations one about an isolated system in which there is no ext. force and so deltap=0
and one non-isolated system in which there is an external force acting so deltap=Impulse
My question is, is momentum always conserved in both these situations?

# Textbook Page270 Chapter 9

Water Falls without splashing at a rate of 0.25L/s from a height of 2.6m into a 0.75kg bucket on a scale. If the bucket is originally empty, what does the scale read in newtons 3.00s after water starts to accumalte in it.
It would be very helpful if you could tell me is this question of similar difficultly level to questions on midterm? Just [...]

# Answered: HELP! HW10 Problem 6

Take a look at this answer: http://tutor.leiacademy.org/qa/index.php/62/hw-10-question-6?show=65#a65
Use the elastic collision equations there, you will find the final velocities — pay attention to the directions (signs) of the velocities — ||v_{2i}|| is in the negative x direction so you will need to put in a negative sign t [...]

# HELP! HW10 Problem 6

In this question, v1i=v2i (because v=sqrt(2gh), it doesnt matter the mass). So from elastic collision equations , I get v1f=v1i (because v1i=v2i, so the numerator and denominator are the same, m1+m2). Similarly, we get v2f=v2i, so the heights (for both blocks) after collision are exactly the same as the heights the blocks released. [...]

# Answered: Oscillator equation

Now you have ||\omega||, nice.
At equilibrium, the velocity has its maximum magnitude ||v=\omega A||, which gives you A based on the numbers given in the question.
Then, since at t=5.4 ms, the oscillator is at equilibrium, you would have ||x(t=5.4 ms)=0||. Plug in the t, A, and ||\omega||, you can find ||\phi _0||.

# Oscillator equation

An oscillator with period 2.7 ms passes through equilibrium at t = 5.4 ms with velocity v = -6.8 m/s. The equation of the oscillator’s motion is
x(t) = ( ? ) cm cos ( ( ( ? ) /s ) t + ( ? ) )
For the second question mark I did 1/2.7 (the period) to get the [...]

# Answered: Homework 10 Question 7

Use energy conservation, we can find the initial vertical velocity of the water droplets with $$\frac 12mv^2=mgh$$
For the adjacent two water droplets, we find ||v_1|| and ||v_2||, which also gives ||\omega_1=\frac {v_1}{R}|| and ||\omega_2=\frac {v_2}{R}||.
Between the two droplets, the wheel rotates for a complete circle so i [...]

# Homework 10 Question 7

A bicycle is turned upside down while its owner repairs a flat tire on the rear wheel. A friend spins the front wheel, of radius 0.342 m, and observes that drops of water fly off tangentially in an upward direction when the drops are at the same level as the center of the wheel. She measures the height reached by drops moving vertically (see [...]

# Answered: HW 10 Question 9

More Physics Homework Help at LeiAcademy.
The blocks are going to slide with acceleration to the right and down the ramp.
Do free body diagrams for the two blocks and the pulley. Define the positive direction being clock wise for the rotation and towards right and down the ramp.
For block 1, you would have 4 forces with ||N_1=m_1g|| and ||f_ [...]

# Answered: HW 10 Question 6

For this question, you first use energy conservation to find the velocities of each of the blocks before the collision. The collision is elastic, so both kinetic energy and momentum are conserved. The calculations are complicated so you can use the elastic collision equations directly to find their final velocities.
$$v_{1f}=\frac {m_1-m_2}{m [...]

# Answered: Hw 11 Problem 5

For simple harmonic oscillation, you have $$x(t)=Acos(\omega t+\phi _0)$$ $$v(t)=-\omega Asin(\omega t+\phi _0)$$ $$a(t)=-\omega ^2Acos(\omega t+\phi _0)$$
Set ||t=0|| as the initial state and we have: $$x(0)=Acos(\omega 0+\phi _0)$$ $$v(0)=-\omega Asin(\omega 0+\phi _0)$$ $$a(0)=-\omega ^2Acos(\omega 0+\phi _0)$$
To find ||\omega||, divide t [...]

# Answered: Ranking periods of oscillat...

In (e), the motion is damped oscillation. The resistive force would slightly decrease the frequency and thus increase its period. Also your ranking seems reversed to what you were discussing — e.g. in (d), k is increased significantly, so T would decrease and be the smallest among all.

# HW 10 Question 6

So I am having problems solving for the height of Block M2 after the collision. I have gotten the height of block one through the conservation of energy and momentum methods, and tried to re-substitute values and it was incorrect. Help?

# Ranking periods of oscillating motion...

A block with mass m = 0.4 kg oscillates with amplitude A = 0.4 m at the end of a spring with force constant k = 15 N/m on a frictionless, horizontal surface. Rank the periods of the following oscillating systems from greatest to smallest. If any periods are equal, show their equality in your ranking. (Use only “>” or “=&# [...]

# Answered: prelab 10 part 4

If the spring is stretched to provide a force -kx, and if the cart is stationary, the net force on the cart should be zero. The key to the question in Web Assign may be incorrect.

# Answered: What are the final speed an...

In this collision problem, the total momentum would be conserved ||P_i=P_f||.
Assume astronaut 1 is on the left and 2 on the right. So the velocity of the apple is in +x direction and the velocity of the orange is towards -x. The momentum before collision:$$\sum P_{xi}=M_a(1.05)+M_o(-1.19)$$ $$\sum P_{yi}=0$$
After the collision, $$\sum [...]

# prelab 10 part 4

In the lab, we have a cart on a ramp tilted at angle θ and attached to a spring at the top of the ramp. When the spring is stretched, what is the magnitude of the total force on the cart?