differentiate between conduction convection and radiation as a means of transportation of energy state the equation for each and explain each symbol used

How much energy is required to accelerate a spaceship with a rest mass of 107 metric tons to a speed of 0.458 c?

Every day our Earth receives 1.55×10²² J energy from the Sun. If we were able to use 0.85 percent of this energy to accelerate spaceships, then how many missions would be possible in one year?

A solenoid having an inductance of 9.13 μH is connected in series with a 1.62 kΩ resistor. (a) If a 16.0 V battery is connected across the pair, how long will it take in seconds for the current through the resistor to reach 82.8% of its final value? (b) What is the current through the resistor at a time t = 1.00τL?

While taking a shower, you notice that the shower head is made up of 36 small round openings, each with a radius of 1.4 mm. You also determine that it takes 7.0 s for the shower to completely fill a 1- liter container you hold in the water stream. The water in your house is pumped by a pump in the basement, 6.2 m below the level of the shower head. The pump maintains an absolute pressure of 1.6 atmospheres. Neglect viscosity. Use g = 9.8 m/s/s, and 1 atmosphere = 101,300 Pa.

[1 point] (a) What is the total area of the openings in the shower head?

[2 points] (b) At what speed is the water emerging from the holes?

cconnected to the pump (assume it has a constant cross-sectional area)?

[2 points] (c) At what speed is the water flowing through the pipe

[2 points] (d) What is the radius of the pipe?

[1 point] (e) If you covered up six of the holes in the shower head with your thumb, with what speed would you expect the water to emerge from the remaining holes?

1. Describe a scenario where two objects are electrically attracted to one another, but one of the objects is neutral in charge

2. What would happen if the force of gravity was stronger than the electrical force between two charges in space?

A bat flying at 4.80 m/s is chasing an insect flying in the same direction. The bat emits a 40.0-kHz chirp and receives back an echo at 40.4 kHz. (Take the speed of sound in air to be 340 m/s.)

What is speed of insect (m/s)

Problem 9: Suppose that a 115 kg football player running at 5.5 m/s catches a 0.47 kg ball moving at a speed of 25.5 m/s with his feet off the ground, while both of them are moving horizontally.

Part (a) Calculate the final speed of the player, in meters per second, if the ball and player are initially moving in the same direction. Numeric : A numeric value is expected and not an expression. vf,1 = __________________________________________

Part (b) Calculate the change in kinetic energy of the system, in joules, after the player catches the ball. Numeric : A numeric value is expected and not an expression. ΔKE1 = __________________________________________

Part (c) Calculate the final speed of the player, in meters per second, if the ball and player are initially moving in opposite directions. Numeric : A numeric value is expected and not an expression. vf,2 = __________________________________________

Part (d) Calculate the change in kinetic energy of the system, in joules, in this case. Numeric : A numeric value is expected and not an expression. ΔKE2 = __________________________________________

A sheet of glass (n=1.50) is coated with a 500 nm -thick layer of oil (n=1.42).

A. For what visible wavelengths of light do the reflected waves interfere constructively? The range of wavelength of visible light is from 380 nm to 750 nm.

B. For what visible wavelengths of light do the reflected waves interfere destructively?

C. What is the color of reflected light?

D. What is the color of transmitted light?

A rock is suspended by a light string. When the rock is in air, the tension in the string is 52.9 N . When the rock is totally immersed in water, the tension is 32.6 N . When the rock is totally immersed in an unknown liquid, the tension is 14.4 N .

What is the density of the unknown liquid?

Ohm’s Law in terms of the applied potential. But we can re-express the potential as the integral of the electric field along some path. We can also re-express electrical resistance in terms of conductivity, length, and cross-section. Use these relationships to write Ohm’s Law in terms of the electric field and the current density.  What physical parameter does a linear fit to the slope of the resistor current graph represent? Why is a similar graphical analysis of the diode current not appropriate?

A series ac circuit consists of a voltage source of frequency f = 60 Hz and source voltage amplitude 345 volts, a resistor of resistance R = 255 Ω, a capacitor of capacitance C = 6.2×10−6F, and an inductor of inductance L.

(a) What must be the value of L for the phase angle Φ to be zero?

(b) When L has the value calculated in (a), what is the current amplitude in the circuit?

A wagon is rolling forward on level ground. Friction is negligible. The person sitting in the wagon is holding a rock. The total mass of the wagon, rider, and rock is 98.9 kg. The mass of the rock is 0.291 kg. Initially the wagon is rolling forward at a speed of 0.490 m/s. Then the person throws the rock with a speed of 16.1 m/s. Both speeds are relative to the ground. Find the speed of the wagon after the rock is thrown (a) directly forward in one case and (b) directly backward in another.

A copper collar is to fit tightly about a steel shaft whose diameter is 7.0000 cm at 20° C. The inside diameter of the copper collar at that temperature is 6.9760 cm. After the collar is heated and fitted about the steel shaft, it begins to cool. What is the tensile stress in the copper collar when its temperature returns to 20° C?

____________________N/m2

A vertical spring (ignore its mass), whose spring constant is 825 N/m , is attached to a table and is compressed down by 0.160 m.

A)What upward speed can it give to a 0.360-kg ball when released? Express your answer to three significant figures and include the appropriate units.

B) How high above its original position (spring compressed) will the ball fly? Express your answer to three significant figures and include the appropriate units.

A 123 turn circular coil of radius 2.27 cm is immersed in a uniform magnetic field that is perpendicular to the plane of the coil. Over an interval of 0.167 s , the magnetic field strength increases from 54.5 mT to 94.1 mT . Find the magnitude of the average emf avg induced in the coil during this time interval, in millivolts.