题目

A device that stops drivers from falling asleep at the wheel is about to undergo testing at Department of Transport laboratories and could go on sale within 12 months. The system, called Driver Alert, aims to reduce deadly road accidents by 20% - 40% that are caused by tiredness. Airline pilots can also use it to reduce the 30% of all pilot-error accidents that are related to fatigue. Driver Alert is based on a computerized wristband (腕套). The device, worn by drivers or pilots, gives out a sound about every four minutes during a car journey. After each sound the driver must respond张老师的质量大约为60     ，他用1N的力沿水平方向推一辆在水平桌面上的小车，小车以较慢的速度沿力的方向做匀速直线运动；当他推着小车以较快的速度在水平桌面上沿力的方向做匀速直线运动时，所用的推力应该     1N（选填“大于”、“小于”或“等于”）．