If you roll a ball down a ramp, which factor will have the greatest effect on the amount of friction created? (a) Force applied to the ball (b) Speed of the ball (c) Texture of the surface (d) Weight of the ramp

Large helium-filled balloons are used to lift scientific equipment to high altitudes. what is the pressure inside such a balloon if it starts out at sea level with a temperature of 10.0ºc and rises to an altitude where its volume is twenty times the original volume and its temperature is – 50.0ºc ?