9. A system comprising: one or more processors; and one or more computer readable storage media including instructions configured to cause the one or more processors to perform operations including: displaying a user interface on a display; while displaying the user interface on the display, detecting an input on an input device, wherein the input includes a motion component and a pressure component; and in response to detecting the input: determining whether the pressure component of the input is above a pressure threshold; in accordance with a determination that the pressure component of the input is above the pressure threshold, performing a first operation in the user interface displayed on the display in accordance with the motion component of the input, wherein the first operation is scrolling content in the user interface at a variable scroll rate that increases and then decays over time, and performing the first operation in the user interface includes causing the user interface to rapidly scroll through content for an initial predetermined time interval and subsequently reduce a scroll rate over a second subsequent predetermined time interval gradually decaying the scroll rate to zero; and in accordance with a determination that pressure component of the input is below the pressure threshold, performing a second operation in the user interface displayed on the display in accordance with the motion component of the input, wherein the second operation is different from the first operation and is scrolling content in the user interface at a predetermined scroll rate.
9. A system comprising: one or more processors; and one or more computer readable storage media including instructions configured to cause the one or more processors to perform operations including: displaying a user interface on a display; while displaying the user interface on the display, detecting an input on an input device, wherein the input includes a motion component and a pressure component; and in response to detecting the input: determining whether the pressure component of the input is above a pressure threshold; in accordance with a determination that the pressure component of the input is above the pressure threshold, performing a first operation in the user interface displayed on the display in accordance with the motion component of the input, wherein the first operation is scrolling content in the user interface at a variable scroll rate that increases and then decays over time, and performing the first operation in the user interface includes causing the user interface to rapidly scroll through content for an initial predetermined time interval and subsequently reduce a scroll rate over a second subsequent predetermined time interval gradually decaying the scroll rate to zero; and in accordance with a determination that pressure component of the input is below the pressure threshold, performing a second operation in the user interface displayed on the display in accordance with the motion component of the input, wherein the second operation is different from the first operation and is scrolling content in the user interface at a predetermined scroll rate. 10. The system of claim 9 , wherein the first operation is rapidly scrolling through the user interface and wherein the second operation is slowly scrolling through the user interface.