A hockey puck is given an initial velocity of 39.6 m/s along the ice. Find the speed of the puck 1.08 s later if the coefficient of kinetic friction between puck and ice is 0.618. (HINT: The result is independent of the mass of the puck.)

In what ways did Galileo' observations of Venus and Jupiter conflict with the prevailing view at the time?

A cylinder with a piston contains 0.300 mol of oxygen at 2.00×10⁵ Pa and 340 K . The oxygen may be treated as an ideal gas. The gas first expands isobarically to twice its original volume. It is then compressed isothermally back to its original volume, and finally it is cooled isochorically to its original pressure.

Find the work done by the gas during the initial expansion. W_initial =

Find the heat added to the gas during the initial expansion. Q_{initial =}

Find internal-energy change of the gas during the initial expansion.

Find the work done during the final cooling. W_final

Find the heat added during the final cooling; Q_final

Find the internal-energy change during the final cooling;

Find the internal-energy change during the isothermal compression.

A bicycle wheel is rotating at 41 rpm when the cyclist begins to pedal harder, giving the wheel a constant angular acceleration of 0.50 rad/s2

What is the wheel's angular velocity, in rpm, 9.0 s later?

Problem 26.49: Resolution of the eye, I.

Even if the lenses of our eyes functioned perfectly, our vision would still be limited due to diffraction of light at the pupil.

Part A

Using Rayleigh's criterion, what is the smallest object a person can see clearly at his near point of 22.5 cm with a pupil 2.25 mm in diameter and light of wavelength 498 nm ? (To get a reasonable estimate without having to go through complicated calculations, we'll ignore the effect of the fluid in the eye.)

Part B

Based upon your answer, does it seem that diffraction plays a significant role in limiting our visual acuity?

a block of mass 2.4 kg is sitting on a frictionless ramp with a spring at the bottom that has a spring constant of 490N/m the angle of the ramp with respect to the horizontal is 31 degrees

A.) the block starting from rest slides down the ramp a distance 78 cm before hitting the spring how far in cm is the spring compressed as the block comes to momentary rest?

B.) After the block comes to rest the spring pushes the block back up the ramp how fast in meters per second is the block moving right after it comes off the spring

C.) what is the change of the gravitational potential energy in joules between the original position of the block at the top of the ramp and the position of the block when spring is fully compressed?

4 Neutron interactions within nuclear power systems.

a) Explain with quantification the terms ‘thermal’ and ‘fast’ to describe neutrons.

b) Describe fully three important neutron interactions in a thermal nuclear power reactor.

c) Describe the range of materials in which these neutron interactions occur and their function in a nuclear reactor.

d) Explain the criticality of the power generation process in terms of these reactions and give a relevant equation with explanation.

The average resistivity of the human body (apart from surface resistance of the skin) is about 5.0 Ω⋅mΩ⋅m. The conducting path between the right and left hands can be approximated as a cylinder 1.6 mm long and 0.10 mm in diameter. The skin resistance can be made negligible by soaking the hands in salt water. If skin resistance is negligible, what potential difference between the hands is needed for a lethal shock current of 100 mAmA? (Your result shows that even small potential differences can produce dangerous currents when the skin is damp.)

Gayle runs at a speed of 3.30 m/s and dives on a sled, initially at rest on the top of a frictionless snow-covered hill. After she has descended a vertical distance of 5.00 m, her brother, who is initially at rest, hops on her back and together they continue down the hill. What is their speed at the bottom of the hill if the total vertical drop is 15.0 m? Gayle's mass is 46.0 kg, the sled has a mass of 5.05 kg and her brother has a mass of 30.0 kg.

If there was no energy generated in the solar interior the core of the Sun would ...

Question 1 options:

Question 2 (1 point)

All other things being equal, which of the following conditions would result in more nuclear reactions taking place each second inside the Sun than is currently the case ?

Question 2 options:

Question 3 (1 point)

What part of the Sun do astronomers learn about when they study neutrinos from the Sun

Question 3 options:

Determine the area of a flat piece of metal according to the data in the table below. The answer will need to be correctly stated as: (mean value ± σ_m) units. For example: Area = (3.2 ± 0.2 cm²).

(a)

Determine the mean, standard deviation, and the standard deviation of the mean for the measurements. (Hint: Use Logger Pro to help you make the calculations. Enter your mean values to at least four decimal places, and enter your standard deviations to at least five decimal places.)

A place-kicker must kick a football from a point 36.0 m (about 40 yards) from the goal. Half the crowd hopes the ball will clear the crossbar, which is 3.05 m high. When kicked, the ball leaves the ground with a speed of 22.4 m/s at an angle of 47.0° to the horizontal. (a) By how much does the ball clear or fall short (vertically) of clearing the crossbar? (Enter a negative answer if it falls short.) m (b) Does the ball approach the crossbar (and cross above or beneath it) while still rising or while falling?

Comparison of electric & gravity forces: Two identical blocks are placed 5 m apart. Each has a mass of 2 kg, is electrically neutral, and is made entirely of copper. Note: One copper atom has a mass of 1.055·10-25 kg and contains 29 protons. a.) How many electrons must a neutral copper atom have? 29 Correct: Your answer is correct. electrons b.) Estimate the percentage of a copper atom's mass that is due to: electrons: 0.025 Correct: Your answer is correct. % protons: 45.9 Correct: Your answer is correct. % Do a proton & electron have an equal amount of charge? Of mass? Also, what constitutes the remaining mass of these copper atoms? c.) Estimate how many electrons each of these blocks has within it. 5.50e26 Correct: Your answer is correct. electrons What is the total charge of all these electrons? -8.8e7 Correct: Your answer is correct. C And what is the total charge of all the protons in a block? +8.8e7 Correct: Your answer is correct. C So what is the net charge of each block? 0 Correct: Your answer is correct. C d.) You now remove an equal amount of electrons from each block, so the electric repulsion of the blocks cancels their gravitational attraction to each other. (Note: You may assume the mass of the blocks is not significantly reduced when removing these electrons-- why?) What is the net charge of each block now? 1.72e-10 Correct: Your answer is correct. C How many electrons were removed from each block? Give a number, and then also express this as a percentage of the total number in the block. % Did your answers for this part depend on the distance between the blocks?