A 5.40 g bullet is fired horizontally at two blocks resting on a smooth tabletop, as shown in the top figure. The bullet passes through the first block, with mass 1.20 kg, and embeds itself in the second, with mass 1.80 kg. Speeds of 0.340 m/s and 1.07 m/s, respectively, are thereby imparted to the blocks, as shown in the bottom figure. Neglecting the mass removed from the first block by the bullet, find the speed of the bullet immediately after it emerges from the first block. Then find the bullets original speed.

Given an example of a superconductor and describe in detail, how it is used in daily activities. Make it at least a paragraph please.

The position of a particle in cm is given by x = (3) cos 9?t, where t is in seconds.

Suppose there are two blocks constructed so that one is twice as massive as the other but they both are the same size and shape. If they are both dropped into free fall on, say, the moon, where there is no atmosphere, would they fall at the same rate? If they were dropped on Earth would they still fall at exactly the same rate, would the heavier one fall twice as fast, or something different? Explain what you think happens when the two blocks are dropped on Earth.

Cartman decides to visit Tibet, and there he finds a Tibetan monastery atop a big rock. The only way up is a lift that uses the Atwood machine concept of a counterweight. The lift goes up a distance of 30 meters. When the lift is below the cliff top by 10 meters, assuming it to be basically at rest, Cartman decides to jump back down onto the lift. The pulley is quite massive at 200 kg. Assume the pulley to be in the shape of a perfect disk with a radius of 80 cm. The lift and counterweight both have a mass of 50 kg, and Cartman has a mass of 102 kg. (a) Start out by calculating what velocity Cartman has just as he hits the Atwood machine. (b) Calculate Cartman�s angular momentum relative to the center of the pulley right before he lands on the lift. (c) Apply conservation of angular momentum, including final state contributions from the counterweight, the mass of the lift, the pulley, and Cartman, to calculate what speed Cartman is going down at right after he lands on the lift. (d) Use conservation of energy to calculate how fast Cartman is going down when the lift hits bottom. If Kenny were under the lift, what happened?

An internal explosion breaks an object, initially at rest, into two pieces: A and B. Piece A has 2.4 times the mass of piece B. The energy of 6400 J is released in the explosion. Part A Determine the kinetic energy of piece A after the explosion. Express your answer to two significant figures and include the appropriate units. Part B Determine the kinetic energy of piece B after the explosion. Express your answer to two significant figures and include the appropriate units.

There are three heat transfer mechanisms. Define each type and briefly explain how they work. Additionally define insulation and how it contrasts against these transfer mechanisms

You have a 40- lightbulb and a 100-W bulb.

1. Find the resistances of the 40-W bulb. Take that ΔV = 120 V.

2. Find the resistances of the 100-W bulb. Take that ΔV = 120 V.

3. If the two bulbs are connected separately, which of them will be brighter?

4. If the two bulbs are connected in series to a battery source, which of them will be brighter?

5. If the two bulbs are connected in parallel to a battery source, which of them will be brighter?

A 0.21 kg hockey puck has a velocity of 2.2 m/s toward the east (the +x direction) as it slides over the frictionless surface of an ice hockey rink. What are the:

(a) magnitude and (b) direction of the constant net force that must act on the puck during a 0.43 s time interval to change the puck's velocity to 3.7 m/s toward the west?

and what are the:

(c) magnitude and (d) direction if, instead, the velocity is changed to 3.7 m/s toward the south?

Give your directions as positive (counterclockwise) angles measured from the +x direction.

A red ball is thrown down with an initial speed of 1.3 m/s from a height of 27 meters above the ground. Then, 0.5 seconds after the red ball is thrown, a blue ball is thrown upward with an initial speed of 24.8 m/s, from a height of 0.7 meters above the ground. The force of gravity due to the earth results in the balls each having a constant downward acceleration of 9.81 m/s².

1) What is the speed of the red ball right before it hits the ground?

m/s

Your submissions:

• 23

Computed value:

23

Submitted:

Correct!

2) How long does it take the red ball to reach the ground?

s

Your submissions:

• 2.2

Computed value:

2.2

Submitted:

Correct!

3)

What is the maximum height the blue ball reaches?

m

Your submissions:

• 32.07

Computed value:

32.07

Submitted:

Correct!

4) What is the height of the blue ball 2 seconds after the red ball is thrown?

5) How long after the red ball is thrown are the two balls in the air at the same height?

6) Which statement is true regarding the blue ball?

After it is released and before it hits the ground, the blue ball is always moving faster than the red ball at any given time.

After it is released and before it hits the ground, the blue ball is sometimes moving faster than the red ball at any given time.

After it is released and before it hits the ground, the blue ball is never moving faster than the red ball at any given time.

7) Which statement is true about the red ball?

The acceleration is positive and it is speeding up

The acceleration is negative and it is speeding up

The acceleration is positive and it is slowing down

The acceleration is negative and it is slowing down

A pot of hot water is boiling on your stove.  The pot is in the shape of a round cylinder made of aluminum which is 10 cm in radius.  The aluminum is 3 mm thick.  You notice that after 22 minutes, 0.13 kg of water has boiled away.

A. What is the temperature of the inner surface of the bottom of the pot?

B. How much energy is required to boil away M kg of water?

C. What is the difference in temperature between the inner and outer sufaces of the aluminum bottom of the pot?

D. What is the change in entropy of the boiling water after boiling away 0.13 kg of water?

The figure is a section of a conducting rod of radius R₁ = 1.20 mm and length L = 13.80 m inside a thin-walled coaxial conducting cylindrical shell of radius R₂ = 10.1R₁ and the (same) length L. The net charge on the rod is Q₁ = +3.41 × 10^-12 C; that on the shell is Q₂ = -2.33Q₁. What are the (a) magnitude E and (b) direction (radially inward or outward) of the electric field at radial distance r = 2.10R₂? What are (c) E and (d) the direction at r = 5.31R₁? What is the charge on the (e) interior and (f) exterior surface of the shell?

A 75.0 kg ice hockey goalie, originally at rest, catches a 0.150 kg hockey puck slapped at him at a velocity of 18.0 m/s. Suppose the goalie and the ice puck have an elastic collision and the puck is reflected back in the direction from which it came. What would their final velocities (in m/s) be in this case? (Assume the original direction of the ice puck toward the goalie is in the positive direction. Indicate the direction with the sign of your answer.)

puck ____ m/s

goalie ____ m/s

An 80 kg skydiver falls through air with a density of 1.15 kg/m3 . Assume that his drag coefficient is C=0.57. When he falls in the spread-eagle position his body presents an area A1=0.94 m2 to the wind, whereas when he dives head first, with arms close to the body and legs together his area is reduced to A2=0.21 m2 . What are the terminal speeds in both cases?

In a particular Millikan oil-drop apparatus, the plates are 2.25 cm apart. The oil used has a density of 0.815 g/cm3 , and the atomizer that sprays the oil drops produces drops of diameter 1.00×10⁻³ mm.  

A) What strength of electric field is needed to hold such a drop stationary against gravity if the drop contains five extra electrons?

B) What should be the potential difference across the plates to produce this electric field?

C) If another drop of the same oil requires a plate potential of 65.3 V to hold it stationary, how many excess electrons did it contain?