9) 7) A magnifying glass has a converging lens of focal length 15 cm. At what distance from a postage stamp should you hold the lens to get a magnification of +2

59. Conduction is A) the direct transmission iof energy without the need for a medium of transfer. B) the transfer of heat via bulk motion of the medium. C) the transfer of heat by electron and atomic collisions. D) the only way to transfer heat from a colder object to a warmer ones. 60. Convection is A) the direct transmission of energy without the need for a medium of transfer. B) the transfer of heat via bulk motion of the medium. C) the transfer of heat by electron and atomic collisions. D) the only way to transfer heat from a colder object to a warmer ones. 58. When you touch the metal handle of the room -temperature stainless-steel frying pan, it feels cool to your touch. When you grab a room-temperature sauce pan by its plastic handle, A) it feels cooler than the metal handle because plastic conducts heat better than the metallic steel. B) it feels warmer than the metal handle because the steel handle conducts heat better than the plastic. C) it doesn't feel cooler or warmer than the steel. Why would it? Both handles are at room temperature! 2 points 2 points 2 points

Concavity can be discerned from a table of values but not from a graph. A True B False

Question 7 (10 points) A relativistic train is moving at 0.6 c relative to the Earth A rocket of proper length 50m is observed to be 30m long by the observers in the train , as the rocket rushes past the train moving parallel to the train and in the same direction. What is the rocket's speed relative to Earth? 0.93 c 0.80 c 1.33 c None of the other answers 0.60 c 0.50 c

River water stored behind a dam is best described as a form of __ thermodynamics chemical energy entropy kinetic energy potential energy

A metal rod of mass m carrying a current I glides on two horizontal 'rails a distance d apart. If the coefficient of kinetic friction between the rod and rails is $\mu _{k'}$ what vertical magnetic field is required to keep the rod moving at a constant speed? (Use any variable or symbol stated above along with the following as necessary: g.) $B=\frac {\mu _{k}mg}{Id}$

Heat is measured in British Thermal Units (Btu). A Btu is defined as the amount of heat required to raise the temperature of one pound of water by 1 degree Fahrenheit. True False

Which of the following is true for electromagnetic waves? They require a medium for propagation. They are longitudinal waves. They have different speeds in vacuum for different frequencies. They are transverse waves.

An object falls from rest. How far does it fall in 3.0 seconds?

A boat accelerates from $15m/s$ to $25m/s$ in 4 seconds. How far does it travel in this time? Give the answer as a number only. Do not include units __

A javelin is thrown with an initial velocity of $30m/s$ at an angle of $35^{\circ }$ above the horizontal. What is the total time of flight for the javelin? Round all intermediate values and final answer to two decimal places __ This is a required question