Calculate the magnitude of the normal force on a 15.2 kg block in the following circumstances. (Enter your answers in N.) (a) The block is resting on a level surface. N (b) The block is resting on a surface tilted up at a 35.8 angle with respect to the horizontal. N (c) The block is resting on the floor of an elevator that is accelerating upward at 3.53 m/s N (d) The block is on a level surface and a force of 155 N is exerted on it at an angle of 35.8 below the horizontal. N

If you wanted to move an electron from the positive to the negative terminal of the battery, how much work w would you need to do on the electron? enter your answer numerically in joules.

1. what is the relationship between wavelength and the penetrating power of an electromagnetic wave? a) the penetrating power has no relationship to the wavelength. b) the penetrating power increases as the wavelength increases. c) the penetrating power decreases as the wavelength increases. d) the penetrating power decreases as the wavelength decreases. 2. as ice melts and turns into water, the speed of sound through the material would most likely do what? justify your answer. a) the speed would not change because the material is always water. b) the speed of sound would increase because the density of water is less than that of ice. c) the speed of sound would increase because energy is added to ice in order to make it melt. d) the speed of sound would decrease because sound travels faster through solids than liquids. 3.which of these waves need a medium to travel through? a) sound b) x-rays c) infrared rays d) visible light

What is the wavelength of an earthquake wave if it has a speed of 8 km/s and a frequency of 3 hz?