Explain the difference between variables and controls in a scientific experiment. what is the purpose of a control?

Free runners jump long distances and land on the ground or a wall. how do they apply newton’s second law to lessen the force of impact?

Which object is most likely represented by a dot?

At 20∘c, the hole in an aluminum ring is 2.800 cm in diameter. you need to slip this ring over a steel shaft that has a room-temperature diameter of 2.804 cm . 1. to what common temperature should the ring and the shaft be heated so that the ring will just fit onto the shaft? coefficients of linear thermal expansion of steel and aluminum are 12×10−6 k−1 and23×10−6 k−1 respectively.