A student conducts an experiment in which sound waves pass through air and then through water Which statement describes the wave speed as it passes from air to water? (1 point) The speed of sound becomes zero The speed of sound decreases The speed of sound increases The speed of sound remains the same

Two bicyclists are accelerating forward at the same rate. Biker 1 has less mass than Biker 2 Which statement describes the net force on the bikers? A. The net force on Biker 1 is in the backwards direction. B. The net force on Biker 2 is greater than on Biker 1. C. The net force on both bikers is changing. D. Both bikers experience the same net force.

Which best describes what forms in nuclear fusion? two smaller,more stable nuclei two larger,less stable nuclei one smaller,less stable nucleus one larger ,more stable nucleus

Part 1-True/False $(20\% )$ Write "True" if the Statement is correct or "False" if it is incorrect on the separate answer sheet 1. A machine can change one form of energy in to another form of energy 2. A lever multiply force and energy at the same time. 3. When the load is greater than the effort, it is said to be force multiplier. 4. Actual mechanical advantage is formed if there is no waste of energy because of friction. 5. If the mechanical advantage is greater than one the machine is a force mu 6. Spring is a type of simple machine. 7. Fishing pole is an example of third class lever. 8. Inclined plane is used to multiply speed. 9. A machine produces an output force of $\frac {1}{2}$ times the input force The machine is said to be force multiplier. 10. The velocity ratio of single fixed pulley is 2. Part II:- Multiple choices $(56\% )$ Choose the correct answer from the given alternatives and write the letter of your choice on the separate answer sheet. 11. A cold steel spoon is dipped in a cup of hot milk. It transfers heat to its other end by the processes of A. radiation C. convection B. absorption D. conduction 12. What is the quantity of heat energy required to heat a 10kg block of copper from 300 K 340 K? ( use specific heat capacity of $copper=420J/kgK$ A. 168 KJ C. 168 J B. 125 KJ D. 125J 13. Calculate the increase in length of a 40 cm brass rod that is heated from $30^{\circ }C$ to $50^{\circ }C$ (linear expansion of Brass is $1.9\times 10^{-5}K^{-1}$ A. 0.51 cm B.1.9 cm C. 0.015 cm D. 15.20 cm

What is the diameter of the Sun [in units of Km] according to your measured $\frac {d}{h}$ HINT: The distance to the sun is $1.5\times 10^{8}Km$ NOTE: To use scientific notation in numerical answers you can use the following, enter 1e5 for $1\times 10^{5}$ this works as in computers $ex=\times 10^{x}$ As an example to enter $5000=5\times 10^{3}$ you would type 5e3 $\square $

36. What kind of interference occurs between two identical waves moving in opposite direction and the two waves are out of phase? A. Constructive C. Destructive B. Bothe constructive and destructive D. Impossible to determine 37. Imagine you are sitting in a room and someone is playing kirar outside and next to your room.You may be able to hear the sound of the kirar through the open door way,you cannot see kirarist. This is because of A. reflection C. diffraction B. interference D. refraction art III. Blank space( $6\% )$ 38. The reflection of sound is __ 39. The quantity of heat needed to raise the temperature of 1 Kg of a substance through $1C^{0}$ or lK is __ 40. The energy that flow from high temperature to low temperature is __

Which of the following exhibit the Tyndall Effect? A laser beam through a soda drink. A flashlight beam through air in a room. Car headlights on a foggy night. A laser beam through salt water.

What happens when you push the button of a doorbell? The current going through the doorbell rapidly switches directions. The electromagnet becomes stronger. The switch is closed. completing the circuit.

When loading a small boat such as a canoe or kayak,how should most of the weight be placed? mostly in the bow balanced and low balanced and high mostly in the stern

Because lightning is electricity, strike victims are not safe to touch after they have been struck. True False

A scientist makes a measurement and gets a value of 90.6 m The true value is 60.0 m. Calculate the absolute and relative error of the scientist's measurement. Round your answers to a reasonable n number of decimal places.Also be sure your answers include any necessary symbols. absolute error: $\square $ relative error: $\square $