A car is moving in a foured direction with the speed of 40 knlph it changes the speed into 80km/h within aminted the acceleration
of the car.

When the force acting on an object points at least partially in the direction of the motion the work done is considered to be negative

What does si stand for,when referring to a system of measurement

In an old-fashioned amusement park ride, passengers stand inside a 3.0-m-tall, 5.0-m-diameter hollow steel cylinder with their backs against the wall. the cylinder begins to rotate about a vertical axis. then the floor on which the passengers are standing suddenly drops away! if all goes well, the passengers will “stick” to the wall and not slide. clothing has a static coefficient of friction against steel in the range 0.60 to 1.0 and a kinetic coefficient in the range 0.40 to 0.70. part a what is the minimum rotational frequency, in rpm, for which the ride is safe? express your answer using two significant figures. f f = rpm