Question 3.Two forces are acting on a 30-kg object, 200 N up and 300 N down. What is the magnitude and direction of its acceleration?

A. It is 100 m/s2 upward,

B. It is 100 m/s2 downward.

C. It is 3 m/s2 upward.

D. It is 3 m/s2 downward.

Why is it important always to use horizontal bars in unit fractions when performing unit conversions?

Glass has a hardness that is in the middle of the hardness scale. what is the hardness of glass?

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