(Q018) The Earth is round because a. the gravitational tug of the Moon has worn down the jagged edges. b. the solar wind has shaped it. c. erosion over time has worn down the jagged edges of its planetesimals. d. its interior rock is warm enough to flow slowly in response to gravity.

20. threshold braking in the vehicle's braking system occurs when a. the brake pedal is pushed, heel on floorboard, with full foot pressure. b. the brakes are exerting full braking power, without traction loss. c. the driver begins pushing down the brake pedal, with moderate slowdown. d. the brakes just begin to take hold with a gradual slowdown.

We put a force of 50n on an object and the acceleration is 100 m/s². what is the mass of the object?

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.