A 0.300-kg puck, initially at rest on a horizontal, frictionless surface, is struck by a 0.200-kg puck moving initially along the x axis with a speed of 2.00 m/s. After the collision, the 0.200- kg puck has a speed of 1.00 m/s at an angle of θ = 53.0° to the positive x axis. (a) Determine the velocity of the 0.300-kg puck after the collision. (b) Find the fraction of kinetic energy lost in the collision.

and please explain

Explain the relationship between GAST and UT1? What is the relationship between UT1 and UTC?

Consider an aluminum annular disk with an outer radius 63.2 mm and inner radius 7.9 mm. The mass of the disk is 464 grams (HINT: the parameters of the disk are the same as in the previous pre-lab).

The disk is allowed to rotate on a frictionless table with the rotation axis at its center. The disk has a small pulley rigidly mounted at the top concentrically. The pulley's radius is 12.1 mm, and the mass of the pulley is negligible. A string is wrapped around the pulley, and a hanging mass of 19.8 g is tied at the other end of the string. When the mass falls under gravity, it causes the aluminum annular disk to rotate. Ignore the string's mass, and assume that the string's motion is frictionless.

What is the angular speed of the aluminum disk when the mass has fallen 14.5 cm?
ω = _____ rad/s

How long does it take for the mass to reach this point?

t= _____s

Calculate the length of the de broglie wave of an electron and a proton moving with a kinetic energy of 1keV. For what values of kinetic energy will their wavelength be equal to 0.1 nm? m_e = 9.1.10 ³¹kg, e = 1.602.10^-19C, mp = 1.627.10^-27 kg

P1.- A high diver leaves the end of a 5.0 m high diving board and strikes the water 1.3 s later, 3.0 m beyond the end of the board. Considering the diver as a particle, determine: (a) her initial velocity Vo (b) the maximum height reached, (c) the velocity Vf with which she enters the water.

P2.- A rollercoaster moves 200 ft horizontally and then rises 135 ft at an angle of 30 degrees above the horizontal. It next travels 135 ft at an angle of 40 degrees downward. What is its displacement from its starting point?

P3.- A model rocket is launched straight upward with an initial speed of 50 m/s. It accelerates with a constant upward acceleration of 2 m/s2 until its engines stop at an altitude of 150 m.

a) What is the maximum height reached by the rocket?

b) How long after liftoff does the rocket reaches its maximum height?

c) How long is the rocket in the air?

what does the H2 vector in this environment when a magnetic field in the air environment with relative magnetic permeability 1 has a value of H1= 3 ax -4ay +5az and enters the ferromagnetic environment on the xy plane and has a relative magnetic permeability 80 ?

Assessment

Friction

Friction resists motion. If an object is stationary, friction tries to keep it from beginning to move. If an object is moving, friction slows it down and tries to stop it.

In all cases all you need to do is add an extra arrow (vector) to your free-body diagram. This new arrow always points opposite the direction of motion. When you use Newton's law to sum the forces, there will be one more term in the equation.

The magnitude of this new arrow/term is always given by Ff = μ FN where

μ is the "coefficient of friction", a number (theat you generally look up on a table) that tells how hard it is to slide two objects in contact.FN is the "Normal Force", or how hard the surface pushes up on the object. Generally you find the Normal force by summing all the forces in the y-direction and solving for FN. Most often however, if there aren't any forces acting in the y-direction other than gravity and the normal force, then for horizontal surfaces, FN = mg. Therefore, Ff = μmgfor inclined plane surfaces, FN = mg cos θ. Therefore, Ff = μmg cos θ

Question 1 (1 point)

Match the following formulas about calculating friction:

Question 1 options:

123

Always works. FN can be found by summing all the y-dir forces, recognizing that the acceleration in the y-dir is (probably) zero, and solve for FN

123

Works whenever the surface is an inclined plane and there are no y-direction forces except for gravity and the normal force

123

Works whenever the surface is horizontal and there are no y-direction forces except for gravity and the normal force

1.

Ff = μmg

2.

Ff = μmg cos θ

3.

Ff = μ FN

Question 6 (1 point)

A 3 kg box sits on a ramp of 6 degrees where the coefficient of friction is 0.2. A 24 N force pulls the box uphill. Find the acceleration.

Your Answer:

Question 6 options:

Answer

Question 7 (1 point)

A 2 kg box sits on a ramp where the coefficient of friction is 0.4. Find the angle that will cause the box to slide downhill at constant velocity.

Hints:

constant velocity means a = 0 sum the forces (downhill pull and friction) and solve for θsin θ / cos θ = tan θtake the arctan

Your Answer:

Question 7 options:

Answer

Question 8 (1 point)

A 2 kg box sits on a ramp of 14 degrees where the coefficient of friction is 0.4. A string runs uphill over a pulley and back down to a hanging mass of 7 kg. Assuming the box on the ramp is pulled uphill by the weight of the hanging mass, find the acceleration.

Your Answer:

Question 8 options:

Answer

Question 9 (1 point)

A 2 kg box sits on a ramp of 14 degrees where the coefficient of friction is 0.2. A string runs uphill over a pulley and back down to a hanging mass of 9 kg. Assuming the box on the ramp is pulled uphill by the weight of the hanging mass, find the acceleration.

Your Answer:

Question 9 options:

Answer

Submit Assessment0 of 9 questions saved

1. A 5.40 g coin is placed 17.0 cm from the center of a turntable. The coin has static and kinetic coefficients of friction with the turntable surface of μs = 0.810 and μk = 0.460.

Part A: What is the maximum angular velocity with which the turntable can spin without the coin sliding? Express your answer with the appropriate units.

2. A 800 g ball moves in a vertical circle on a 1.09 m -long string. If the speed at the top is 4.30 m/s , then the speed at the bottom will be 7.82 m/s .

Part A: What is the ball's weight? Express your answer with the appropriate units.

Part B: What is the tension in the string when the ball is at the top? Express your answer with the appropriate units.

Part C: What is the tension in the string when the ball is at the bottom? Express your answer with the appropriate units.

1. Advanced skiers turn by sliding the backs of their skis across the snow. Since the fronts of their skis don’t move much, the skis end up pointed in a new direction.

a. The amount of sideways force that a skier must exert on the skis to slide them sideways is proportional to how hard the skis press down on the snow beneath them. Why?

b. Less skilled skiers sometimes turn without unweighting—they push their skis sideways so hard that the skis slide anyway. This technique is exhausting. Why does it require so much work?

c. Why is wax used on skis? Why wouldn’t WD-40 work as well as the wax? What is in WD-40?

A Kaon K⁺ breaks down into two particles. From amongst the following three particles:

π⁰ (neutral pion)

η⁰ (eta meson)

μ⁺ (anti-muon, identical to a muon except for its electric charge)

which one(s) can be formed as the products of the described break-down? (the other product is not known).

a. π⁰

b. η⁰

c. μ⁺

d. η⁰, π⁰

e. μ⁺, π⁰

f. μ⁺, η⁰

g. all three of them

h. none of them

Please reason your answer based on the various laws of conservation, and explain in precise terms why each one the three particles can or cannot be the product of the breakdown.

Thank you!

An acoustic signal is composed of the first three harmonics of a wave of fundamental frequency 425 Hz. If these harmonics are described, in order, by cosine waves with amplitudes of 0.630, 0.900, and 0.650, what is the total amplitude of the signal at time 0.825 seconds? Assume the waves have phase angles θ_n = 0.

List and briefly discuss three significant considerations when measuring very small currents. this qiestion is related to photoelectric effect lab

1. A new car is tested on a 290-m-diameter track. If the car speeds up at a steady 1.2 m/s2 , how long after starting is the magnitude of its centripetal acceleration equal to the tangential acceleration? Express your answer to two significant figures and include the appropriate units.

2. A concrete highway curve of radius 80.0 m is banked at a 15.0 ∘ angle.

Part A: What is the maximum speed with which a 1300 kg rubber-tired car can take this curve without sliding? (Take the static coefficient of friction of rubber on concrete to be 1.0.) Express your answer with the appropriate units.

3. A 4 kg ball swings in a vertical circle on the end of an 80-cm-long string. The tension in the string is 20 N when its angle from the highest point on the circle is θ=30∘.

Part A: What is the ball's speed when θ=30∘? Express your answer to two significant figures and include the appropriate units.

Part B: What is the magnitude of the ball's acceleration when θ=30∘? Express your answer to two significant figures and include the appropriate units.

Part C: What is the direction of the ball's acceleration when θ=30∘? Give the direction as an angle from the r-axis. Express your answer to two significant figures and include the appropriate units.